linux/fs/ecryptfs/inode.c

1183 lines
32 KiB

ecryptfs: inode: Help out nearly-there header and demote non-conformant ones Fixes the following W=1 kernel build warning(s): fs/ecryptfs/inode.c:27: warning: Function parameter or member 'dentry' not described in 'lock_parent' fs/ecryptfs/inode.c:27: warning: Function parameter or member 'lower_dentry' not described in 'lock_parent' fs/ecryptfs/inode.c:27: warning: Function parameter or member 'lower_dir' not described in 'lock_parent' fs/ecryptfs/inode.c:27: warning: expecting prototype for eCryptfs(). Prototype was for lock_parent() instead fs/ecryptfs/inode.c:211: warning: Function parameter or member 'ecryptfs_dentry' not described in 'ecryptfs_initialize_file' fs/ecryptfs/inode.c:211: warning: Function parameter or member 'ecryptfs_inode' not described in 'ecryptfs_initialize_file' fs/ecryptfs/inode.c:258: warning: Function parameter or member 'mnt_userns' not described in 'ecryptfs_create' fs/ecryptfs/inode.c:258: warning: Function parameter or member 'directory_inode' not described in 'ecryptfs_create' fs/ecryptfs/inode.c:258: warning: Function parameter or member 'ecryptfs_dentry' not described in 'ecryptfs_create' fs/ecryptfs/inode.c:258: warning: Function parameter or member 'excl' not described in 'ecryptfs_create' fs/ecryptfs/inode.c:258: warning: Excess function parameter 'dir' description in 'ecryptfs_create' fs/ecryptfs/inode.c:258: warning: Excess function parameter 'dentry' description in 'ecryptfs_create' fs/ecryptfs/inode.c:320: warning: Function parameter or member 'dentry' not described in 'ecryptfs_lookup_interpose' fs/ecryptfs/inode.c:320: warning: Function parameter or member 'lower_dentry' not described in 'ecryptfs_lookup_interpose' fs/ecryptfs/inode.c:887: warning: Function parameter or member 'mnt_userns' not described in 'ecryptfs_setattr' Cc: Tyler Hicks <code@tyhicks.com> Cc: "Michael A. Halcrow" <mahalcro@us.ibm.com> Cc: "Michael C. Thompsion" <mcthomps@us.ibm.com> Cc: ecryptfs@vger.kernel.org Signed-off-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Tyler Hicks <code@tyhicks.com>
2021-03-30 17:44:57 +01:00
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 17:04:11 +09:00
ecryptfs: fix unlink and rmdir in face of underlying fs modifications A problem similar to the one caught in commit 74dd7c97ea2a ("ecryptfs_rename(): verify that lower dentries are still OK after lock_rename()") exists for unlink/rmdir as well. Instead of playing with dget_parent() of underlying dentry of victim and hoping it's the same as underlying dentry of our directory, do the following: * find the underlying dentry of victim * find the underlying directory of victim's parent (stable since the victim is ecryptfs dentry and inode of its parent is held exclusive by the caller). * lock the inode of dentry underlying the victim's parent * check that underlying dentry of victim is still hashed and has the right parent - it can be moved, but it can't be moved to/from the directory we are holding exclusive. So while ->d_parent itself might not be stable, the result of comparison is. If the check passes, everything is fine - underlying directory is locked, underlying victim is still a child of that directory and we can go ahead and feed them to vfs_unlink(). As in the current mainline we need to pin the underlying dentry of victim, so that it wouldn't go negative under us, but that's the only temporary reference that needs to be grabbed there. Underlying dentry of parent won't go away (it's pinned by the parent, which is held by caller), so there's no need to grab it. The same problem (with the same solution) exists for rmdir. Moreover, rename gets simpler and more robust with the same "don't bother with dget_parent()" approach. Fixes: 74dd7c97ea2 "ecryptfs_rename(): verify that lower dentries are still OK after lock_rename()" Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-11-03 12:07:15 -05:00
vfs-6.19-rc1.directory.locking -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCaSmOZwAKCRCRxhvAZXjc op9tAQCJ//STOkvYHfqgsdRD+cW9MRg/gPzfVZgnV1FTyf8sMgEA0IsY5zCZB9eh 9FdD0E57P8PlWRwWZ+LktnWBzRAUqwI= =MOVR -----END PGP SIGNATURE----- Merge tag 'vfs-6.19-rc1.directory.locking' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull directory locking updates from Christian Brauner: "This contains the work to add centralized APIs for directory locking operations. This series is part of a larger effort to change directory operation locking to allow multiple concurrent operations in a directory. The ultimate goal is to lock the target dentry(s) rather than the whole parent directory. To help with changing the locking protocol, this series centralizes locking and lookup in new helper functions. The helpers establish a pattern where it is the dentry that is being locked and unlocked (currently the lock is held on dentry->d_parent->d_inode, but that can change in the future). This also changes vfs_mkdir() to unlock the parent on failure, as well as dput()ing the dentry. This allows end_creating() to only require the target dentry (which may be IS_ERR() after vfs_mkdir()), not the parent" * tag 'vfs-6.19-rc1.directory.locking' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: nfsd: fix end_creating() conversion VFS: introduce end_creating_keep() VFS: change vfs_mkdir() to unlock on failure. ecryptfs: use new start_creating/start_removing APIs Add start_renaming_two_dentries() VFS/ovl/smb: introduce start_renaming_dentry() VFS/nfsd/ovl: introduce start_renaming() and end_renaming() VFS: add start_creating_killable() and start_removing_killable() VFS: introduce start_removing_dentry() smb/server: use end_removing_noperm for for target of smb2_create_link() VFS: introduce start_creating_noperm() and start_removing_noperm() VFS/nfsd/cachefiles/ovl: introduce start_removing() and end_removing() VFS/nfsd/cachefiles/ovl: add start_creating() and end_creating() VFS: tidy up do_unlinkat() VFS: introduce start_dirop() and end_dirop() debugfs: rename end_creating() to debugfs_end_creating()
2025-12-01 16:13:46 -08:00
ecryptfs: inode: Help out nearly-there header and demote non-conformant ones Fixes the following W=1 kernel build warning(s): fs/ecryptfs/inode.c:27: warning: Function parameter or member 'dentry' not described in 'lock_parent' fs/ecryptfs/inode.c:27: warning: Function parameter or member 'lower_dentry' not described in 'lock_parent' fs/ecryptfs/inode.c:27: warning: Function parameter or member 'lower_dir' not described in 'lock_parent' fs/ecryptfs/inode.c:27: warning: expecting prototype for eCryptfs(). Prototype was for lock_parent() instead fs/ecryptfs/inode.c:211: warning: Function parameter or member 'ecryptfs_dentry' not described in 'ecryptfs_initialize_file' fs/ecryptfs/inode.c:211: warning: Function parameter or member 'ecryptfs_inode' not described in 'ecryptfs_initialize_file' fs/ecryptfs/inode.c:258: warning: Function parameter or member 'mnt_userns' not described in 'ecryptfs_create' fs/ecryptfs/inode.c:258: warning: Function parameter or member 'directory_inode' not described in 'ecryptfs_create' fs/ecryptfs/inode.c:258: warning: Function parameter or member 'ecryptfs_dentry' not described in 'ecryptfs_create' fs/ecryptfs/inode.c:258: warning: Function parameter or member 'excl' not described in 'ecryptfs_create' fs/ecryptfs/inode.c:258: warning: Excess function parameter 'dir' description in 'ecryptfs_create' fs/ecryptfs/inode.c:258: warning: Excess function parameter 'dentry' description in 'ecryptfs_create' fs/ecryptfs/inode.c:320: warning: Function parameter or member 'dentry' not described in 'ecryptfs_lookup_interpose' fs/ecryptfs/inode.c:320: warning: Function parameter or member 'lower_dentry' not described in 'ecryptfs_lookup_interpose' fs/ecryptfs/inode.c:887: warning: Function parameter or member 'mnt_userns' not described in 'ecryptfs_setattr' Cc: Tyler Hicks <code@tyhicks.com> Cc: "Michael A. Halcrow" <mahalcro@us.ibm.com> Cc: "Michael C. Thompsion" <mcthomps@us.ibm.com> Cc: ecryptfs@vger.kernel.org Signed-off-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Tyler Hicks <code@tyhicks.com>
2021-03-30 17:44:57 +01:00
ecryptfs: inode: Help out nearly-there header and demote non-conformant ones Fixes the following W=1 kernel build warning(s): fs/ecryptfs/inode.c:27: warning: Function parameter or member 'dentry' not described in 'lock_parent' fs/ecryptfs/inode.c:27: warning: Function parameter or member 'lower_dentry' not described in 'lock_parent' fs/ecryptfs/inode.c:27: warning: Function parameter or member 'lower_dir' not described in 'lock_parent' fs/ecryptfs/inode.c:27: warning: expecting prototype for eCryptfs(). Prototype was for lock_parent() instead fs/ecryptfs/inode.c:211: warning: Function parameter or member 'ecryptfs_dentry' not described in 'ecryptfs_initialize_file' fs/ecryptfs/inode.c:211: warning: Function parameter or member 'ecryptfs_inode' not described in 'ecryptfs_initialize_file' fs/ecryptfs/inode.c:258: warning: Function parameter or member 'mnt_userns' not described in 'ecryptfs_create' fs/ecryptfs/inode.c:258: warning: Function parameter or member 'directory_inode' not described in 'ecryptfs_create' fs/ecryptfs/inode.c:258: warning: Function parameter or member 'ecryptfs_dentry' not described in 'ecryptfs_create' fs/ecryptfs/inode.c:258: warning: Function parameter or member 'excl' not described in 'ecryptfs_create' fs/ecryptfs/inode.c:258: warning: Excess function parameter 'dir' description in 'ecryptfs_create' fs/ecryptfs/inode.c:258: warning: Excess function parameter 'dentry' description in 'ecryptfs_create' fs/ecryptfs/inode.c:320: warning: Function parameter or member 'dentry' not described in 'ecryptfs_lookup_interpose' fs/ecryptfs/inode.c:320: warning: Function parameter or member 'lower_dentry' not described in 'ecryptfs_lookup_interpose' fs/ecryptfs/inode.c:887: warning: Function parameter or member 'mnt_userns' not described in 'ecryptfs_setattr' Cc: Tyler Hicks <code@tyhicks.com> Cc: "Michael A. Halcrow" <mahalcro@us.ibm.com> Cc: "Michael C. Thompsion" <mcthomps@us.ibm.com> Cc: ecryptfs@vger.kernel.org Signed-off-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Tyler Hicks <code@tyhicks.com>
2021-03-30 17:44:57 +01:00
ecryptfs: inode: Help out nearly-there header and demote non-conformant ones Fixes the following W=1 kernel build warning(s): fs/ecryptfs/inode.c:27: warning: Function parameter or member 'dentry' not described in 'lock_parent' fs/ecryptfs/inode.c:27: warning: Function parameter or member 'lower_dentry' not described in 'lock_parent' fs/ecryptfs/inode.c:27: warning: Function parameter or member 'lower_dir' not described in 'lock_parent' fs/ecryptfs/inode.c:27: warning: expecting prototype for eCryptfs(). Prototype was for lock_parent() instead fs/ecryptfs/inode.c:211: warning: Function parameter or member 'ecryptfs_dentry' not described in 'ecryptfs_initialize_file' fs/ecryptfs/inode.c:211: warning: Function parameter or member 'ecryptfs_inode' not described in 'ecryptfs_initialize_file' fs/ecryptfs/inode.c:258: warning: Function parameter or member 'mnt_userns' not described in 'ecryptfs_create' fs/ecryptfs/inode.c:258: warning: Function parameter or member 'directory_inode' not described in 'ecryptfs_create' fs/ecryptfs/inode.c:258: warning: Function parameter or member 'ecryptfs_dentry' not described in 'ecryptfs_create' fs/ecryptfs/inode.c:258: warning: Function parameter or member 'excl' not described in 'ecryptfs_create' fs/ecryptfs/inode.c:258: warning: Excess function parameter 'dir' description in 'ecryptfs_create' fs/ecryptfs/inode.c:258: warning: Excess function parameter 'dentry' description in 'ecryptfs_create' fs/ecryptfs/inode.c:320: warning: Function parameter or member 'dentry' not described in 'ecryptfs_lookup_interpose' fs/ecryptfs/inode.c:320: warning: Function parameter or member 'lower_dentry' not described in 'ecryptfs_lookup_interpose' fs/ecryptfs/inode.c:887: warning: Function parameter or member 'mnt_userns' not described in 'ecryptfs_setattr' Cc: Tyler Hicks <code@tyhicks.com> Cc: "Michael A. Halcrow" <mahalcro@us.ibm.com> Cc: "Michael C. Thompsion" <mcthomps@us.ibm.com> Cc: ecryptfs@vger.kernel.org Signed-off-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Tyler Hicks <code@tyhicks.com>
2021-03-30 17:44:57 +01:00
VFS: rename lookup_one_len family to lookup_noperm and remove permission check The lookup_one_len family of functions is (now) only used internally by a filesystem on itself either - in a context where permission checking is irrelevant such as by a virtual filesystem populating itself, or xfs accessing its ORPHANAGE or dquota accessing the quota file; or - in a context where a permission check (MAY_EXEC on the parent) has just been performed such as a network filesystem finding in "silly-rename" file in the same directory. This is also the context after the _parentat() functions where currently lookup_one_qstr_excl() is used. So the permission check is pointless. The name "one_len" is unhelpful in understanding the purpose of these functions and should be changed. Most of the callers pass the len as "strlen()" so using a qstr and QSTR() can simplify the code. This patch renames these functions (include lookup_positive_unlocked() which is part of the family despite the name) to have a name based on "lookup_noperm". They are changed to receive a 'struct qstr' instead of separate name and len. In a few cases the use of QSTR() results in a new call to strlen(). try_lookup_noperm() takes a pointer to a qstr instead of the whole qstr. This is consistent with d_hash_and_lookup() (which is nearly identical) and useful for lookup_noperm_unlocked(). The new lookup_noperm_common() doesn't take a qstr yet. That will be tidied up in a subsequent patch. Signed-off-by: NeilBrown <neil@brown.name> Link: https://lore.kernel.org/r/20250319031545.2999807-5-neil@brown.name Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-03-19 14:01:35 +11:00
VFS: rename lookup_one_len family to lookup_noperm and remove permission check The lookup_one_len family of functions is (now) only used internally by a filesystem on itself either - in a context where permission checking is irrelevant such as by a virtual filesystem populating itself, or xfs accessing its ORPHANAGE or dquota accessing the quota file; or - in a context where a permission check (MAY_EXEC on the parent) has just been performed such as a network filesystem finding in "silly-rename" file in the same directory. This is also the context after the _parentat() functions where currently lookup_one_qstr_excl() is used. So the permission check is pointless. The name "one_len" is unhelpful in understanding the purpose of these functions and should be changed. Most of the callers pass the len as "strlen()" so using a qstr and QSTR() can simplify the code. This patch renames these functions (include lookup_positive_unlocked() which is part of the family despite the name) to have a name based on "lookup_noperm". They are changed to receive a 'struct qstr' instead of separate name and len. In a few cases the use of QSTR() results in a new call to strlen(). try_lookup_noperm() takes a pointer to a qstr instead of the whole qstr. This is consistent with d_hash_and_lookup() (which is nearly identical) and useful for lookup_noperm_unlocked(). The new lookup_noperm_common() doesn't take a qstr yet. That will be tidied up in a subsequent patch. Signed-off-by: NeilBrown <neil@brown.name> Link: https://lore.kernel.org/r/20250319031545.2999807-5-neil@brown.name Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-03-19 14:01:35 +11:00
VFS: rename lookup_one_len family to lookup_noperm and remove permission check The lookup_one_len family of functions is (now) only used internally by a filesystem on itself either - in a context where permission checking is irrelevant such as by a virtual filesystem populating itself, or xfs accessing its ORPHANAGE or dquota accessing the quota file; or - in a context where a permission check (MAY_EXEC on the parent) has just been performed such as a network filesystem finding in "silly-rename" file in the same directory. This is also the context after the _parentat() functions where currently lookup_one_qstr_excl() is used. So the permission check is pointless. The name "one_len" is unhelpful in understanding the purpose of these functions and should be changed. Most of the callers pass the len as "strlen()" so using a qstr and QSTR() can simplify the code. This patch renames these functions (include lookup_positive_unlocked() which is part of the family despite the name) to have a name based on "lookup_noperm". They are changed to receive a 'struct qstr' instead of separate name and len. In a few cases the use of QSTR() results in a new call to strlen(). try_lookup_noperm() takes a pointer to a qstr instead of the whole qstr. This is consistent with d_hash_and_lookup() (which is nearly identical) and useful for lookup_noperm_unlocked(). The new lookup_noperm_common() doesn't take a qstr yet. That will be tidied up in a subsequent patch. Signed-off-by: NeilBrown <neil@brown.name> Link: https://lore.kernel.org/r/20250319031545.2999807-5-neil@brown.name Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-03-19 14:01:35 +11:00
VFS: rename lookup_one_len family to lookup_noperm and remove permission check The lookup_one_len family of functions is (now) only used internally by a filesystem on itself either - in a context where permission checking is irrelevant such as by a virtual filesystem populating itself, or xfs accessing its ORPHANAGE or dquota accessing the quota file; or - in a context where a permission check (MAY_EXEC on the parent) has just been performed such as a network filesystem finding in "silly-rename" file in the same directory. This is also the context after the _parentat() functions where currently lookup_one_qstr_excl() is used. So the permission check is pointless. The name "one_len" is unhelpful in understanding the purpose of these functions and should be changed. Most of the callers pass the len as "strlen()" so using a qstr and QSTR() can simplify the code. This patch renames these functions (include lookup_positive_unlocked() which is part of the family despite the name) to have a name based on "lookup_noperm". They are changed to receive a 'struct qstr' instead of separate name and len. In a few cases the use of QSTR() results in a new call to strlen(). try_lookup_noperm() takes a pointer to a qstr instead of the whole qstr. This is consistent with d_hash_and_lookup() (which is nearly identical) and useful for lookup_noperm_unlocked(). The new lookup_noperm_common() doesn't take a qstr yet. That will be tidied up in a subsequent patch. Signed-off-by: NeilBrown <neil@brown.name> Link: https://lore.kernel.org/r/20250319031545.2999807-5-neil@brown.name Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-03-19 14:01:35 +11:00
VFS: rename lookup_one_len family to lookup_noperm and remove permission check The lookup_one_len family of functions is (now) only used internally by a filesystem on itself either - in a context where permission checking is irrelevant such as by a virtual filesystem populating itself, or xfs accessing its ORPHANAGE or dquota accessing the quota file; or - in a context where a permission check (MAY_EXEC on the parent) has just been performed such as a network filesystem finding in "silly-rename" file in the same directory. This is also the context after the _parentat() functions where currently lookup_one_qstr_excl() is used. So the permission check is pointless. The name "one_len" is unhelpful in understanding the purpose of these functions and should be changed. Most of the callers pass the len as "strlen()" so using a qstr and QSTR() can simplify the code. This patch renames these functions (include lookup_positive_unlocked() which is part of the family despite the name) to have a name based on "lookup_noperm". They are changed to receive a 'struct qstr' instead of separate name and len. In a few cases the use of QSTR() results in a new call to strlen(). try_lookup_noperm() takes a pointer to a qstr instead of the whole qstr. This is consistent with d_hash_and_lookup() (which is nearly identical) and useful for lookup_noperm_unlocked(). The new lookup_noperm_common() doesn't take a qstr yet. That will be tidied up in a subsequent patch. Signed-off-by: NeilBrown <neil@brown.name> Link: https://lore.kernel.org/r/20250319031545.2999807-5-neil@brown.name Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-03-19 14:01:35 +11:00
VFS: rename lookup_one_len family to lookup_noperm and remove permission check The lookup_one_len family of functions is (now) only used internally by a filesystem on itself either - in a context where permission checking is irrelevant such as by a virtual filesystem populating itself, or xfs accessing its ORPHANAGE or dquota accessing the quota file; or - in a context where a permission check (MAY_EXEC on the parent) has just been performed such as a network filesystem finding in "silly-rename" file in the same directory. This is also the context after the _parentat() functions where currently lookup_one_qstr_excl() is used. So the permission check is pointless. The name "one_len" is unhelpful in understanding the purpose of these functions and should be changed. Most of the callers pass the len as "strlen()" so using a qstr and QSTR() can simplify the code. This patch renames these functions (include lookup_positive_unlocked() which is part of the family despite the name) to have a name based on "lookup_noperm". They are changed to receive a 'struct qstr' instead of separate name and len. In a few cases the use of QSTR() results in a new call to strlen(). try_lookup_noperm() takes a pointer to a qstr instead of the whole qstr. This is consistent with d_hash_and_lookup() (which is nearly identical) and useful for lookup_noperm_unlocked(). The new lookup_noperm_common() doesn't take a qstr yet. That will be tidied up in a subsequent patch. Signed-off-by: NeilBrown <neil@brown.name> Link: https://lore.kernel.org/r/20250319031545.2999807-5-neil@brown.name Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-03-19 14:01:35 +11:00
VFS: rename lookup_one_len family to lookup_noperm and remove permission check The lookup_one_len family of functions is (now) only used internally by a filesystem on itself either - in a context where permission checking is irrelevant such as by a virtual filesystem populating itself, or xfs accessing its ORPHANAGE or dquota accessing the quota file; or - in a context where a permission check (MAY_EXEC on the parent) has just been performed such as a network filesystem finding in "silly-rename" file in the same directory. This is also the context after the _parentat() functions where currently lookup_one_qstr_excl() is used. So the permission check is pointless. The name "one_len" is unhelpful in understanding the purpose of these functions and should be changed. Most of the callers pass the len as "strlen()" so using a qstr and QSTR() can simplify the code. This patch renames these functions (include lookup_positive_unlocked() which is part of the family despite the name) to have a name based on "lookup_noperm". They are changed to receive a 'struct qstr' instead of separate name and len. In a few cases the use of QSTR() results in a new call to strlen(). try_lookup_noperm() takes a pointer to a qstr instead of the whole qstr. This is consistent with d_hash_and_lookup() (which is nearly identical) and useful for lookup_noperm_unlocked(). The new lookup_noperm_common() doesn't take a qstr yet. That will be tidied up in a subsequent patch. Signed-off-by: NeilBrown <neil@brown.name> Link: https://lore.kernel.org/r/20250319031545.2999807-5-neil@brown.name Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-03-19 14:01:35 +11:00
Change inode_operations.mkdir to return struct dentry * Some filesystems, such as NFS, cifs, ceph, and fuse, do not have complete control of sequencing on the actual filesystem (e.g. on a different server) and may find that the inode created for a mkdir request already exists in the icache and dcache by the time the mkdir request returns. For example, if the filesystem is mounted twice the directory could be visible on the other mount before it is on the original mount, and a pair of name_to_handle_at(), open_by_handle_at() calls could instantiate the directory inode with an IS_ROOT() dentry before the first mkdir returns. This means that the dentry passed to ->mkdir() may not be the one that is associated with the inode after the ->mkdir() completes. Some callers need to interact with the inode after the ->mkdir completes and they currently need to perform a lookup in the (rare) case that the dentry is no longer hashed. This lookup-after-mkdir requires that the directory remains locked to avoid races. Planned future patches to lock the dentry rather than the directory will mean that this lookup cannot be performed atomically with the mkdir. To remove this barrier, this patch changes ->mkdir to return the resulting dentry if it is different from the one passed in. Possible returns are: NULL - the directory was created and no other dentry was used ERR_PTR() - an error occurred non-NULL - this other dentry was spliced in This patch only changes file-systems to return "ERR_PTR(err)" instead of "err" or equivalent transformations. Subsequent patches will make further changes to some file-systems to return a correct dentry. Not all filesystems reliably result in a positive hashed dentry: - NFS, cifs, hostfs will sometimes need to perform a lookup of the name to get inode information. Races could result in this returning something different. Note that this lookup is non-atomic which is what we are trying to avoid. Placing the lookup in filesystem code means it only happens when the filesystem has no other option. - kernfs and tracefs leave the dentry negative and the ->revalidate operation ensures that lookup will be called to correctly populate the dentry. This could be fixed but I don't think it is important to any of the users of vfs_mkdir() which look at the dentry. The recommendation to use d_drop();d_splice_alias() is ugly but fits with current practice. A planned future patch will change this. Reviewed-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: NeilBrown <neilb@suse.de> Link: https://lore.kernel.org/r/20250227013949.536172-2-neilb@suse.de Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-27 12:32:53 +11:00
VFS: Change vfs_mkdir() to return the dentry. vfs_mkdir() does not guarantee to leave the child dentry hashed or make it positive on success, and in many such cases the filesystem had to use a different dentry which it can now return. This patch changes vfs_mkdir() to return the dentry provided by the filesystems which is hashed and positive when provided. This reduces the number of cases where the resulting dentry is not positive to a handful which don't deserve extra efforts. The only callers of vfs_mkdir() which are interested in the resulting inode are in-kernel filesystem clients: cachefiles, nfsd, smb/server. The only filesystems that don't reliably provide the inode are: - kernfs, tracefs which these clients are unlikely to be interested in - cifs in some configurations would need to do a lookup to find the created inode, but doesn't. cifs cannot be exported via NFS, is unlikely to be used by cachefiles, and smb/server only has a soft requirement for the inode, so this is unlikely to be a problem in practice. - hostfs, nfs, cifs may need to do a lookup (rarely for NFS) and it is possible for a race to make that lookup fail. Actual failure is unlikely and providing callers handle negative dentries graceful they will fail-safe. So this patch removes the lookup code in nfsd and smb/server and adjusts them to fail safe if a negative dentry is provided: - cache-files already fails safe by restarting the task from the top - it still does with this change, though it no longer calls cachefiles_put_directory() as that will crash if the dentry is negative. - nfsd reports "Server-fault" which it what it used to do if the lookup failed. This will never happen on any file-systems that it can actually export, so this is of no consequence. I removed the fh_update() call as that is not needed and out-of-place. A subsequent nfsd_create_setattr() call will call fh_update() when needed. - smb/server only wants the inode to call ksmbd_smb_inherit_owner() which updates ->i_uid (without calling notify_change() or similar) which can be safely skipping on cifs (I hope). If a different dentry is returned, the first one is put. If necessary the fact that it is new can be determined by comparing pointers. A new dentry will certainly have a new pointer (as the old is put after the new is obtained). Similarly if an error is returned (via ERR_PTR()) the original dentry is put. Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: NeilBrown <neilb@suse.de> Link: https://lore.kernel.org/r/20250227013949.536172-7-neilb@suse.de Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-27 12:32:58 +11:00
VFS: Change vfs_mkdir() to return the dentry. vfs_mkdir() does not guarantee to leave the child dentry hashed or make it positive on success, and in many such cases the filesystem had to use a different dentry which it can now return. This patch changes vfs_mkdir() to return the dentry provided by the filesystems which is hashed and positive when provided. This reduces the number of cases where the resulting dentry is not positive to a handful which don't deserve extra efforts. The only callers of vfs_mkdir() which are interested in the resulting inode are in-kernel filesystem clients: cachefiles, nfsd, smb/server. The only filesystems that don't reliably provide the inode are: - kernfs, tracefs which these clients are unlikely to be interested in - cifs in some configurations would need to do a lookup to find the created inode, but doesn't. cifs cannot be exported via NFS, is unlikely to be used by cachefiles, and smb/server only has a soft requirement for the inode, so this is unlikely to be a problem in practice. - hostfs, nfs, cifs may need to do a lookup (rarely for NFS) and it is possible for a race to make that lookup fail. Actual failure is unlikely and providing callers handle negative dentries graceful they will fail-safe. So this patch removes the lookup code in nfsd and smb/server and adjusts them to fail safe if a negative dentry is provided: - cache-files already fails safe by restarting the task from the top - it still does with this change, though it no longer calls cachefiles_put_directory() as that will crash if the dentry is negative. - nfsd reports "Server-fault" which it what it used to do if the lookup failed. This will never happen on any file-systems that it can actually export, so this is of no consequence. I removed the fh_update() call as that is not needed and out-of-place. A subsequent nfsd_create_setattr() call will call fh_update() when needed. - smb/server only wants the inode to call ksmbd_smb_inherit_owner() which updates ->i_uid (without calling notify_change() or similar) which can be safely skipping on cifs (I hope). If a different dentry is returned, the first one is put. If necessary the fact that it is new can be determined by comparing pointers. A new dentry will certainly have a new pointer (as the old is put after the new is obtained). Similarly if an error is returned (via ERR_PTR()) the original dentry is put. Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: NeilBrown <neilb@suse.de> Link: https://lore.kernel.org/r/20250227013949.536172-7-neilb@suse.de Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-27 12:32:58 +11:00
ecryptfs: Release lower parent dentry after creating dir Fix a mkdir-induced usage count imbalance that tripped a umount_check() BUG while unmounting the lower filesystem. Commit f046fbb4d81d ("ecryptfs: use new start_creating/start_removing APIs") added a new dget() of the lower parent dir, in ecryptfs_mkdir(), but did not dput() the dentry before returning from that function. The BUG output as seen while running the eCryptfs test suite: $ ./run_tests.sh -b 131072 -c safe,destructive -f ext4 -K -t lp-926292.sh ... Running eCryptfs filesystem tests on ext4 lp-926292 ------------[ cut here ]------------ BUG: Dentry ffff8e6692d11988{i=c,n=ECRYPTFS_FNEK_ENCRYPTED.FXZuRGZL7QAFtER.JeA46DtdKqkkQx9H2Vpmv234J5CU8YSsrUwZJK4AbXbrN5WkZ348wnqstovKKxA-} still in use (1) [unmount of ext4 loop0] WARNING: CPU: 7 PID: 950 at fs/dcache.c:1590 umount_check+0x5e/0x80 Modules linked in: md5 libmd5 ecryptfs encrypted_keys ext4 crc16 mbcache jbd2 CPU: 7 UID: 0 PID: 950 Comm: umount Not tainted 6.18.0-rc1-00013-gf046fbb4d81d #17 PREEMPT(full) Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 RIP: 0010:umount_check+0x5e/0x80 Code: 88 38 06 00 00 48 8b 40 28 4c 8b 08 48 8b 46 68 48 85 c0 74 04 48 8b 50 38 51 48 c7 c7 60 32 9c b5 48 89 f1 e8 43 5e ca ff 90 <0f> 0b 90 90 58 31 c0 e9 46 9d 6c 00 41 83 f8 01 75 b8 eb a3 66 66 RSP: 0018:ffffa19940c4bdd0 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff8e6692fad4c0 RCX: 0000000000000000 RDX: 0000000000000004 RSI: ffffa19940c4bc70 RDI: 00000000ffffffff RBP: ffffffffb4eb5930 R08: 00000000ffffdfff R09: 0000000000000001 R10: 00000000ffffdfff R11: ffffffffb5c8a9e0 R12: ffff8e6692fad4c0 R13: ffff8e6692fad4c0 R14: ffff8e6692d11a40 R15: ffff8e6692d11988 FS: 00007f6b4b491800(0000) GS:ffff8e670506e000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6b4b5f8d40 CR3: 0000000114eb7001 CR4: 0000000000772ef0 PKRU: 55555554 Call Trace: <TASK> d_walk+0xfd/0x370 shrink_dcache_for_umount+0x4d/0x140 generic_shutdown_super+0x20/0x160 kill_block_super+0x1a/0x40 ext4_kill_sb+0x22/0x40 [ext4] deactivate_locked_super+0x33/0xa0 cleanup_mnt+0xba/0x150 task_work_run+0x5c/0xa0 exit_to_user_mode_loop+0xac/0xb0 do_syscall_64+0x2ab/0xfa0 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6b4b6c2a2b Code: c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 f3 0f 1e fa 31 f6 e9 05 00 00 00 0f 1f 44 00 00 f3 0f 1e fa b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 8b 15 b9 83 0d 00 f7 d8 RSP: 002b:00007ffcd5b8b498 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 000055b84af0b9e0 RCX: 00007f6b4b6c2a2b RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000055b84af0bdf0 RBP: 00007ffcd5b8b570 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000103 R11: 0000000000000246 R12: 000055b84af0bae0 R13: 0000000000000000 R14: 000055b84af0bdf0 R15: 0000000000000000 </TASK> ---[ end trace 0000000000000000 ]--- EXT4-fs (loop0): unmounting filesystem 00d9ea41-f61e-43d0-a449-6be03e7e8428. EXT4-fs (loop0): sb orphan head is 12 sb_info orphan list: inode loop0:12 at ffff8e66950e1df0: mode 40700, nlink 0, next 0 Assertion failure in ext4_put_super() at fs/ext4/super.c:1345: 'list_empty(&sbi->s_orphan)' Fixes: f046fbb4d81d ("ecryptfs: use new start_creating/start_removing APIs") Signed-off-by: Tyler Hicks <code@tyhicks.com> Link: https://patch.msgid.link/20251223194153.2818445-3-code@tyhicks.com Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-12-23 13:41:53 -06:00
Change inode_operations.mkdir to return struct dentry * Some filesystems, such as NFS, cifs, ceph, and fuse, do not have complete control of sequencing on the actual filesystem (e.g. on a different server) and may find that the inode created for a mkdir request already exists in the icache and dcache by the time the mkdir request returns. For example, if the filesystem is mounted twice the directory could be visible on the other mount before it is on the original mount, and a pair of name_to_handle_at(), open_by_handle_at() calls could instantiate the directory inode with an IS_ROOT() dentry before the first mkdir returns. This means that the dentry passed to ->mkdir() may not be the one that is associated with the inode after the ->mkdir() completes. Some callers need to interact with the inode after the ->mkdir completes and they currently need to perform a lookup in the (rare) case that the dentry is no longer hashed. This lookup-after-mkdir requires that the directory remains locked to avoid races. Planned future patches to lock the dentry rather than the directory will mean that this lookup cannot be performed atomically with the mkdir. To remove this barrier, this patch changes ->mkdir to return the resulting dentry if it is different from the one passed in. Possible returns are: NULL - the directory was created and no other dentry was used ERR_PTR() - an error occurred non-NULL - this other dentry was spliced in This patch only changes file-systems to return "ERR_PTR(err)" instead of "err" or equivalent transformations. Subsequent patches will make further changes to some file-systems to return a correct dentry. Not all filesystems reliably result in a positive hashed dentry: - NFS, cifs, hostfs will sometimes need to perform a lookup of the name to get inode information. Races could result in this returning something different. Note that this lookup is non-atomic which is what we are trying to avoid. Placing the lookup in filesystem code means it only happens when the filesystem has no other option. - kernfs and tracefs leave the dentry negative and the ->revalidate operation ensures that lookup will be called to correctly populate the dentry. This could be fixed but I don't think it is important to any of the users of vfs_mkdir() which look at the dentry. The recommendation to use d_drop();d_splice_alias() is ugly but fits with current practice. A planned future patch will change this. Reviewed-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: NeilBrown <neilb@suse.de> Link: https://lore.kernel.org/r/20250227013949.536172-2-neilb@suse.de Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-27 12:32:53 +11:00
vfs-6.19-rc1.directory.locking -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCaSmOZwAKCRCRxhvAZXjc op9tAQCJ//STOkvYHfqgsdRD+cW9MRg/gPzfVZgnV1FTyf8sMgEA0IsY5zCZB9eh 9FdD0E57P8PlWRwWZ+LktnWBzRAUqwI= =MOVR -----END PGP SIGNATURE----- Merge tag 'vfs-6.19-rc1.directory.locking' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull directory locking updates from Christian Brauner: "This contains the work to add centralized APIs for directory locking operations. This series is part of a larger effort to change directory operation locking to allow multiple concurrent operations in a directory. The ultimate goal is to lock the target dentry(s) rather than the whole parent directory. To help with changing the locking protocol, this series centralizes locking and lookup in new helper functions. The helpers establish a pattern where it is the dentry that is being locked and unlocked (currently the lock is held on dentry->d_parent->d_inode, but that can change in the future). This also changes vfs_mkdir() to unlock the parent on failure, as well as dput()ing the dentry. This allows end_creating() to only require the target dentry (which may be IS_ERR() after vfs_mkdir()), not the parent" * tag 'vfs-6.19-rc1.directory.locking' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: nfsd: fix end_creating() conversion VFS: introduce end_creating_keep() VFS: change vfs_mkdir() to unlock on failure. ecryptfs: use new start_creating/start_removing APIs Add start_renaming_two_dentries() VFS/ovl/smb: introduce start_renaming_dentry() VFS/nfsd/ovl: introduce start_renaming() and end_renaming() VFS: add start_creating_killable() and start_removing_killable() VFS: introduce start_removing_dentry() smb/server: use end_removing_noperm for for target of smb2_create_link() VFS: introduce start_creating_noperm() and start_removing_noperm() VFS/nfsd/cachefiles/ovl: introduce start_removing() and end_removing() VFS/nfsd/cachefiles/ovl: add start_creating() and end_creating() VFS: tidy up do_unlinkat() VFS: introduce start_dirop() and end_dirop() debugfs: rename end_creating() to debugfs_end_creating()
2025-12-01 16:13:46 -08:00
ecryptfs: fix unlink and rmdir in face of underlying fs modifications A problem similar to the one caught in commit 74dd7c97ea2a ("ecryptfs_rename(): verify that lower dentries are still OK after lock_rename()") exists for unlink/rmdir as well. Instead of playing with dget_parent() of underlying dentry of victim and hoping it's the same as underlying dentry of our directory, do the following: * find the underlying dentry of victim * find the underlying directory of victim's parent (stable since the victim is ecryptfs dentry and inode of its parent is held exclusive by the caller). * lock the inode of dentry underlying the victim's parent * check that underlying dentry of victim is still hashed and has the right parent - it can be moved, but it can't be moved to/from the directory we are holding exclusive. So while ->d_parent itself might not be stable, the result of comparison is. If the check passes, everything is fine - underlying directory is locked, underlying victim is still a child of that directory and we can go ahead and feed them to vfs_unlink(). As in the current mainline we need to pin the underlying dentry of victim, so that it wouldn't go negative under us, but that's the only temporary reference that needs to be grabbed there. Underlying dentry of parent won't go away (it's pinned by the parent, which is held by caller), so there's no need to grab it. The same problem (with the same solution) exists for rmdir. Moreover, rename gets simpler and more robust with the same "don't bother with dget_parent()" approach. Fixes: 74dd7c97ea2 "ecryptfs_rename(): verify that lower dentries are still OK after lock_rename()" Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-11-03 12:07:15 -05:00
ecryptfs: fix unlink and rmdir in face of underlying fs modifications A problem similar to the one caught in commit 74dd7c97ea2a ("ecryptfs_rename(): verify that lower dentries are still OK after lock_rename()") exists for unlink/rmdir as well. Instead of playing with dget_parent() of underlying dentry of victim and hoping it's the same as underlying dentry of our directory, do the following: * find the underlying dentry of victim * find the underlying directory of victim's parent (stable since the victim is ecryptfs dentry and inode of its parent is held exclusive by the caller). * lock the inode of dentry underlying the victim's parent * check that underlying dentry of victim is still hashed and has the right parent - it can be moved, but it can't be moved to/from the directory we are holding exclusive. So while ->d_parent itself might not be stable, the result of comparison is. If the check passes, everything is fine - underlying directory is locked, underlying victim is still a child of that directory and we can go ahead and feed them to vfs_unlink(). As in the current mainline we need to pin the underlying dentry of victim, so that it wouldn't go negative under us, but that's the only temporary reference that needs to be grabbed there. Underlying dentry of parent won't go away (it's pinned by the parent, which is held by caller), so there's no need to grab it. The same problem (with the same solution) exists for rmdir. Moreover, rename gets simpler and more robust with the same "don't bother with dget_parent()" approach. Fixes: 74dd7c97ea2 "ecryptfs_rename(): verify that lower dentries are still OK after lock_rename()" Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-11-03 12:07:15 -05:00
vfs-6.19-rc1.directory.locking -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCaSmOZwAKCRCRxhvAZXjc op9tAQCJ//STOkvYHfqgsdRD+cW9MRg/gPzfVZgnV1FTyf8sMgEA0IsY5zCZB9eh 9FdD0E57P8PlWRwWZ+LktnWBzRAUqwI= =MOVR -----END PGP SIGNATURE----- Merge tag 'vfs-6.19-rc1.directory.locking' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull directory locking updates from Christian Brauner: "This contains the work to add centralized APIs for directory locking operations. This series is part of a larger effort to change directory operation locking to allow multiple concurrent operations in a directory. The ultimate goal is to lock the target dentry(s) rather than the whole parent directory. To help with changing the locking protocol, this series centralizes locking and lookup in new helper functions. The helpers establish a pattern where it is the dentry that is being locked and unlocked (currently the lock is held on dentry->d_parent->d_inode, but that can change in the future). This also changes vfs_mkdir() to unlock the parent on failure, as well as dput()ing the dentry. This allows end_creating() to only require the target dentry (which may be IS_ERR() after vfs_mkdir()), not the parent" * tag 'vfs-6.19-rc1.directory.locking' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: nfsd: fix end_creating() conversion VFS: introduce end_creating_keep() VFS: change vfs_mkdir() to unlock on failure. ecryptfs: use new start_creating/start_removing APIs Add start_renaming_two_dentries() VFS/ovl/smb: introduce start_renaming_dentry() VFS/nfsd/ovl: introduce start_renaming() and end_renaming() VFS: add start_creating_killable() and start_removing_killable() VFS: introduce start_removing_dentry() smb/server: use end_removing_noperm for for target of smb2_create_link() VFS: introduce start_creating_noperm() and start_removing_noperm() VFS/nfsd/cachefiles/ovl: introduce start_removing() and end_removing() VFS/nfsd/cachefiles/ovl: add start_creating() and end_creating() VFS: tidy up do_unlinkat() VFS: introduce start_dirop() and end_dirop() debugfs: rename end_creating() to debugfs_end_creating()
2025-12-01 16:13:46 -08:00
ecryptfs: fix unlink and rmdir in face of underlying fs modifications A problem similar to the one caught in commit 74dd7c97ea2a ("ecryptfs_rename(): verify that lower dentries are still OK after lock_rename()") exists for unlink/rmdir as well. Instead of playing with dget_parent() of underlying dentry of victim and hoping it's the same as underlying dentry of our directory, do the following: * find the underlying dentry of victim * find the underlying directory of victim's parent (stable since the victim is ecryptfs dentry and inode of its parent is held exclusive by the caller). * lock the inode of dentry underlying the victim's parent * check that underlying dentry of victim is still hashed and has the right parent - it can be moved, but it can't be moved to/from the directory we are holding exclusive. So while ->d_parent itself might not be stable, the result of comparison is. If the check passes, everything is fine - underlying directory is locked, underlying victim is still a child of that directory and we can go ahead and feed them to vfs_unlink(). As in the current mainline we need to pin the underlying dentry of victim, so that it wouldn't go negative under us, but that's the only temporary reference that needs to be grabbed there. Underlying dentry of parent won't go away (it's pinned by the parent, which is held by caller), so there's no need to grab it. The same problem (with the same solution) exists for rmdir. Moreover, rename gets simpler and more robust with the same "don't bother with dget_parent()" approach. Fixes: 74dd7c97ea2 "ecryptfs_rename(): verify that lower dentries are still OK after lock_rename()" Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-11-03 12:07:15 -05:00
ecryptfs: fix unlink and rmdir in face of underlying fs modifications A problem similar to the one caught in commit 74dd7c97ea2a ("ecryptfs_rename(): verify that lower dentries are still OK after lock_rename()") exists for unlink/rmdir as well. Instead of playing with dget_parent() of underlying dentry of victim and hoping it's the same as underlying dentry of our directory, do the following: * find the underlying dentry of victim * find the underlying directory of victim's parent (stable since the victim is ecryptfs dentry and inode of its parent is held exclusive by the caller). * lock the inode of dentry underlying the victim's parent * check that underlying dentry of victim is still hashed and has the right parent - it can be moved, but it can't be moved to/from the directory we are holding exclusive. So while ->d_parent itself might not be stable, the result of comparison is. If the check passes, everything is fine - underlying directory is locked, underlying victim is still a child of that directory and we can go ahead and feed them to vfs_unlink(). As in the current mainline we need to pin the underlying dentry of victim, so that it wouldn't go negative under us, but that's the only temporary reference that needs to be grabbed there. Underlying dentry of parent won't go away (it's pinned by the parent, which is held by caller), so there's no need to grab it. The same problem (with the same solution) exists for rmdir. Moreover, rename gets simpler and more robust with the same "don't bother with dget_parent()" approach. Fixes: 74dd7c97ea2 "ecryptfs_rename(): verify that lower dentries are still OK after lock_rename()" Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-11-03 12:07:15 -05:00
ecryptfs: fix unlink and rmdir in face of underlying fs modifications A problem similar to the one caught in commit 74dd7c97ea2a ("ecryptfs_rename(): verify that lower dentries are still OK after lock_rename()") exists for unlink/rmdir as well. Instead of playing with dget_parent() of underlying dentry of victim and hoping it's the same as underlying dentry of our directory, do the following: * find the underlying dentry of victim * find the underlying directory of victim's parent (stable since the victim is ecryptfs dentry and inode of its parent is held exclusive by the caller). * lock the inode of dentry underlying the victim's parent * check that underlying dentry of victim is still hashed and has the right parent - it can be moved, but it can't be moved to/from the directory we are holding exclusive. So while ->d_parent itself might not be stable, the result of comparison is. If the check passes, everything is fine - underlying directory is locked, underlying victim is still a child of that directory and we can go ahead and feed them to vfs_unlink(). As in the current mainline we need to pin the underlying dentry of victim, so that it wouldn't go negative under us, but that's the only temporary reference that needs to be grabbed there. Underlying dentry of parent won't go away (it's pinned by the parent, which is held by caller), so there's no need to grab it. The same problem (with the same solution) exists for rmdir. Moreover, rename gets simpler and more robust with the same "don't bother with dget_parent()" approach. Fixes: 74dd7c97ea2 "ecryptfs_rename(): verify that lower dentries are still OK after lock_rename()" Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-11-03 12:07:15 -05:00
2025-10-11 13:00:10 -07:00
VFS: (Scripted) Convert S_ISLNK/DIR/REG(dentry->d_inode) to d_is_*(dentry) Convert the following where appropriate: (1) S_ISLNK(dentry->d_inode) to d_is_symlink(dentry). (2) S_ISREG(dentry->d_inode) to d_is_reg(dentry). (3) S_ISDIR(dentry->d_inode) to d_is_dir(dentry). This is actually more complicated than it appears as some calls should be converted to d_can_lookup() instead. The difference is whether the directory in question is a real dir with a ->lookup op or whether it's a fake dir with a ->d_automount op. In some circumstances, we can subsume checks for dentry->d_inode not being NULL into this, provided we the code isn't in a filesystem that expects d_inode to be NULL if the dirent really *is* negative (ie. if we're going to use d_inode() rather than d_backing_inode() to get the inode pointer). Note that the dentry type field may be set to something other than DCACHE_MISS_TYPE when d_inode is NULL in the case of unionmount, where the VFS manages the fall-through from a negative dentry to a lower layer. In such a case, the dentry type of the negative union dentry is set to the same as the type of the lower dentry. However, if you know d_inode is not NULL at the call site, then you can use the d_is_xxx() functions even in a filesystem. There is one further complication: a 0,0 chardev dentry may be labelled DCACHE_WHITEOUT_TYPE rather than DCACHE_SPECIAL_TYPE. Strictly, this was intended for special directory entry types that don't have attached inodes. The following perl+coccinelle script was used: use strict; my @callers; open($fd, 'git grep -l \'S_IS[A-Z].*->d_inode\' |') || die "Can't grep for S_ISDIR and co. callers"; @callers = <$fd>; close($fd); unless (@callers) { print "No matches\n"; exit(0); } my @cocci = ( '@@', 'expression E;', '@@', '', '- S_ISLNK(E->d_inode->i_mode)', '+ d_is_symlink(E)', '', '@@', 'expression E;', '@@', '', '- S_ISDIR(E->d_inode->i_mode)', '+ d_is_dir(E)', '', '@@', 'expression E;', '@@', '', '- S_ISREG(E->d_inode->i_mode)', '+ d_is_reg(E)' ); my $coccifile = "tmp.sp.cocci"; open($fd, ">$coccifile") || die $coccifile; print($fd "$_\n") || die $coccifile foreach (@cocci); close($fd); foreach my $file (@callers) { chomp $file; print "Processing ", $file, "\n"; system("spatch", "--sp-file", $coccifile, $file, "--in-place", "--no-show-diff") == 0 || die "spatch failed"; } [AV: overlayfs parts skipped] Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-01-29 12:02:35 +00:00
eCryptfs: Check inode changes in setattr Most filesystems call inode_change_ok() very early in ->setattr(), but eCryptfs didn't call it at all. It allowed the lower filesystem to make the call in its ->setattr() function. Then, eCryptfs would copy the appropriate inode attributes from the lower inode to the eCryptfs inode. This patch changes that and actually calls inode_change_ok() on the eCryptfs inode, fairly early in ecryptfs_setattr(). Ideally, the call would happen earlier in ecryptfs_setattr(), but there are some possible inode initialization steps that must happen first. Since the call was already being made on the lower inode, the change in functionality should be minimal, except for the case of a file extending truncate call. In that case, inode_newsize_ok() was never being called on the eCryptfs inode. Rather than inode_newsize_ok() catching maximum file size errors early on, eCryptfs would encrypt zeroed pages and write them to the lower filesystem until the lower filesystem's write path caught the error in generic_write_checks(). This patch introduces a new function, called ecryptfs_inode_newsize_ok(), which checks if the new lower file size is within the appropriate limits when the truncate operation will be growing the lower file. In summary this change prevents eCryptfs truncate operations (and the resulting page encryptions), which would exceed the lower filesystem limits or FSIZE rlimits, from ever starting. Signed-off-by: Tyler Hicks <tyhicks@canonical.com> Reviewed-by: Li Wang <liwang@nudt.edu.cn> Cc: <stable@vger.kernel.org>
2012-01-19 20:33:44 -06:00
eCryptfs: Check inode changes in setattr Most filesystems call inode_change_ok() very early in ->setattr(), but eCryptfs didn't call it at all. It allowed the lower filesystem to make the call in its ->setattr() function. Then, eCryptfs would copy the appropriate inode attributes from the lower inode to the eCryptfs inode. This patch changes that and actually calls inode_change_ok() on the eCryptfs inode, fairly early in ecryptfs_setattr(). Ideally, the call would happen earlier in ecryptfs_setattr(), but there are some possible inode initialization steps that must happen first. Since the call was already being made on the lower inode, the change in functionality should be minimal, except for the case of a file extending truncate call. In that case, inode_newsize_ok() was never being called on the eCryptfs inode. Rather than inode_newsize_ok() catching maximum file size errors early on, eCryptfs would encrypt zeroed pages and write them to the lower filesystem until the lower filesystem's write path caught the error in generic_write_checks(). This patch introduces a new function, called ecryptfs_inode_newsize_ok(), which checks if the new lower file size is within the appropriate limits when the truncate operation will be growing the lower file. In summary this change prevents eCryptfs truncate operations (and the resulting page encryptions), which would exceed the lower filesystem limits or FSIZE rlimits, from ever starting. Signed-off-by: Tyler Hicks <tyhicks@canonical.com> Reviewed-by: Li Wang <liwang@nudt.edu.cn> Cc: <stable@vger.kernel.org>
2012-01-19 20:33:44 -06:00
statx: Add a system call to make enhanced file info available Add a system call to make extended file information available, including file creation and some attribute flags where available through the underlying filesystem. The getattr inode operation is altered to take two additional arguments: a u32 request_mask and an unsigned int flags that indicate the synchronisation mode. This change is propagated to the vfs_getattr*() function. Functions like vfs_stat() are now inline wrappers around new functions vfs_statx() and vfs_statx_fd() to reduce stack usage. ======== OVERVIEW ======== The idea was initially proposed as a set of xattrs that could be retrieved with getxattr(), but the general preference proved to be for a new syscall with an extended stat structure. A number of requests were gathered for features to be included. The following have been included: (1) Make the fields a consistent size on all arches and make them large. (2) Spare space, request flags and information flags are provided for future expansion. (3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an __s64). (4) Creation time: The SMB protocol carries the creation time, which could be exported by Samba, which will in turn help CIFS make use of FS-Cache as that can be used for coherency data (stx_btime). This is also specified in NFSv4 as a recommended attribute and could be exported by NFSD [Steve French]. (5) Lightweight stat: Ask for just those details of interest, and allow a netfs (such as NFS) to approximate anything not of interest, possibly without going to the server [Trond Myklebust, Ulrich Drepper, Andreas Dilger] (AT_STATX_DONT_SYNC). (6) Heavyweight stat: Force a netfs to go to the server, even if it thinks its cached attributes are up to date [Trond Myklebust] (AT_STATX_FORCE_SYNC). And the following have been left out for future extension: (7) Data version number: Could be used by userspace NFS servers [Aneesh Kumar]. Can also be used to modify fill_post_wcc() in NFSD which retrieves i_version directly, but has just called vfs_getattr(). It could get it from the kstat struct if it used vfs_xgetattr() instead. (There's disagreement on the exact semantics of a single field, since not all filesystems do this the same way). (8) BSD stat compatibility: Including more fields from the BSD stat such as creation time (st_btime) and inode generation number (st_gen) [Jeremy Allison, Bernd Schubert]. (9) Inode generation number: Useful for FUSE and userspace NFS servers [Bernd Schubert]. (This was asked for but later deemed unnecessary with the open-by-handle capability available and caused disagreement as to whether it's a security hole or not). (10) Extra coherency data may be useful in making backups [Andreas Dilger]. (No particular data were offered, but things like last backup timestamp, the data version number and the DOS archive bit would come into this category). (11) Allow the filesystem to indicate what it can/cannot provide: A filesystem can now say it doesn't support a standard stat feature if that isn't available, so if, for instance, inode numbers or UIDs don't exist or are fabricated locally... (This requires a separate system call - I have an fsinfo() call idea for this). (12) Store a 16-byte volume ID in the superblock that can be returned in struct xstat [Steve French]. (Deferred to fsinfo). (13) Include granularity fields in the time data to indicate the granularity of each of the times (NFSv4 time_delta) [Steve French]. (Deferred to fsinfo). (14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags. Note that the Linux IOC flags are a mess and filesystems such as Ext4 define flags that aren't in linux/fs.h, so translation in the kernel may be a necessity (or, possibly, we provide the filesystem type too). (Some attributes are made available in stx_attributes, but the general feeling was that the IOC flags were to ext[234]-specific and shouldn't be exposed through statx this way). (15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer, Michael Kerrisk]. (Deferred, probably to fsinfo. Finding out if there's an ACL or seclabal might require extra filesystem operations). (16) Femtosecond-resolution timestamps [Dave Chinner]. (A __reserved field has been left in the statx_timestamp struct for this - if there proves to be a need). (17) A set multiple attributes syscall to go with this. =============== NEW SYSTEM CALL =============== The new system call is: int ret = statx(int dfd, const char *filename, unsigned int flags, unsigned int mask, struct statx *buffer); The dfd, filename and flags parameters indicate the file to query, in a similar way to fstatat(). There is no equivalent of lstat() as that can be emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is also no equivalent of fstat() as that can be emulated by passing a NULL filename to statx() with the fd of interest in dfd. Whether or not statx() synchronises the attributes with the backing store can be controlled by OR'ing a value into the flags argument (this typically only affects network filesystems): (1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this respect. (2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise its attributes with the server - which might require data writeback to occur to get the timestamps correct. (3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a network filesystem. The resulting values should be considered approximate. mask is a bitmask indicating the fields in struct statx that are of interest to the caller. The user should set this to STATX_BASIC_STATS to get the basic set returned by stat(). It should be noted that asking for more information may entail extra I/O operations. buffer points to the destination for the data. This must be 256 bytes in size. ====================== MAIN ATTRIBUTES RECORD ====================== The following structures are defined in which to return the main attribute set: struct statx_timestamp { __s64 tv_sec; __s32 tv_nsec; __s32 __reserved; }; struct statx { __u32 stx_mask; __u32 stx_blksize; __u64 stx_attributes; __u32 stx_nlink; __u32 stx_uid; __u32 stx_gid; __u16 stx_mode; __u16 __spare0[1]; __u64 stx_ino; __u64 stx_size; __u64 stx_blocks; __u64 __spare1[1]; struct statx_timestamp stx_atime; struct statx_timestamp stx_btime; struct statx_timestamp stx_ctime; struct statx_timestamp stx_mtime; __u32 stx_rdev_major; __u32 stx_rdev_minor; __u32 stx_dev_major; __u32 stx_dev_minor; __u64 __spare2[14]; }; The defined bits in request_mask and stx_mask are: STATX_TYPE Want/got stx_mode & S_IFMT STATX_MODE Want/got stx_mode & ~S_IFMT STATX_NLINK Want/got stx_nlink STATX_UID Want/got stx_uid STATX_GID Want/got stx_gid STATX_ATIME Want/got stx_atime{,_ns} STATX_MTIME Want/got stx_mtime{,_ns} STATX_CTIME Want/got stx_ctime{,_ns} STATX_INO Want/got stx_ino STATX_SIZE Want/got stx_size STATX_BLOCKS Want/got stx_blocks STATX_BASIC_STATS [The stuff in the normal stat struct] STATX_BTIME Want/got stx_btime{,_ns} STATX_ALL [All currently available stuff] stx_btime is the file creation time, stx_mask is a bitmask indicating the data provided and __spares*[] are where as-yet undefined fields can be placed. Time fields are structures with separate seconds and nanoseconds fields plus a reserved field in case we want to add even finer resolution. Note that times will be negative if before 1970; in such a case, the nanosecond fields will also be negative if not zero. The bits defined in the stx_attributes field convey information about a file, how it is accessed, where it is and what it does. The following attributes map to FS_*_FL flags and are the same numerical value: STATX_ATTR_COMPRESSED File is compressed by the fs STATX_ATTR_IMMUTABLE File is marked immutable STATX_ATTR_APPEND File is append-only STATX_ATTR_NODUMP File is not to be dumped STATX_ATTR_ENCRYPTED File requires key to decrypt in fs Within the kernel, the supported flags are listed by: KSTAT_ATTR_FS_IOC_FLAGS [Are any other IOC flags of sufficient general interest to be exposed through this interface?] New flags include: STATX_ATTR_AUTOMOUNT Object is an automount trigger These are for the use of GUI tools that might want to mark files specially, depending on what they are. Fields in struct statx come in a number of classes: (0) stx_dev_*, stx_blksize. These are local system information and are always available. (1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino, stx_size, stx_blocks. These will be returned whether the caller asks for them or not. The corresponding bits in stx_mask will be set to indicate whether they actually have valid values. If the caller didn't ask for them, then they may be approximated. For example, NFS won't waste any time updating them from the server, unless as a byproduct of updating something requested. If the values don't actually exist for the underlying object (such as UID or GID on a DOS file), then the bit won't be set in the stx_mask, even if the caller asked for the value. In such a case, the returned value will be a fabrication. Note that there are instances where the type might not be valid, for instance Windows reparse points. (2) stx_rdev_*. This will be set only if stx_mode indicates we're looking at a blockdev or a chardev, otherwise will be 0. (3) stx_btime. Similar to (1), except this will be set to 0 if it doesn't exist. ======= TESTING ======= The following test program can be used to test the statx system call: samples/statx/test-statx.c Just compile and run, passing it paths to the files you want to examine. The file is built automatically if CONFIG_SAMPLES is enabled. Here's some example output. Firstly, an NFS directory that crosses to another FSID. Note that the AUTOMOUNT attribute is set because transiting this directory will cause d_automount to be invoked by the VFS. [root@andromeda ~]# /tmp/test-statx -A /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:26 Inode: 1703937 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------) Secondly, the result of automounting on that directory. [root@andromeda ~]# /tmp/test-statx /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:27 Inode: 2 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-01-31 16:46:22 +00:00
statx: Add a system call to make enhanced file info available Add a system call to make extended file information available, including file creation and some attribute flags where available through the underlying filesystem. The getattr inode operation is altered to take two additional arguments: a u32 request_mask and an unsigned int flags that indicate the synchronisation mode. This change is propagated to the vfs_getattr*() function. Functions like vfs_stat() are now inline wrappers around new functions vfs_statx() and vfs_statx_fd() to reduce stack usage. ======== OVERVIEW ======== The idea was initially proposed as a set of xattrs that could be retrieved with getxattr(), but the general preference proved to be for a new syscall with an extended stat structure. A number of requests were gathered for features to be included. The following have been included: (1) Make the fields a consistent size on all arches and make them large. (2) Spare space, request flags and information flags are provided for future expansion. (3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an __s64). (4) Creation time: The SMB protocol carries the creation time, which could be exported by Samba, which will in turn help CIFS make use of FS-Cache as that can be used for coherency data (stx_btime). This is also specified in NFSv4 as a recommended attribute and could be exported by NFSD [Steve French]. (5) Lightweight stat: Ask for just those details of interest, and allow a netfs (such as NFS) to approximate anything not of interest, possibly without going to the server [Trond Myklebust, Ulrich Drepper, Andreas Dilger] (AT_STATX_DONT_SYNC). (6) Heavyweight stat: Force a netfs to go to the server, even if it thinks its cached attributes are up to date [Trond Myklebust] (AT_STATX_FORCE_SYNC). And the following have been left out for future extension: (7) Data version number: Could be used by userspace NFS servers [Aneesh Kumar]. Can also be used to modify fill_post_wcc() in NFSD which retrieves i_version directly, but has just called vfs_getattr(). It could get it from the kstat struct if it used vfs_xgetattr() instead. (There's disagreement on the exact semantics of a single field, since not all filesystems do this the same way). (8) BSD stat compatibility: Including more fields from the BSD stat such as creation time (st_btime) and inode generation number (st_gen) [Jeremy Allison, Bernd Schubert]. (9) Inode generation number: Useful for FUSE and userspace NFS servers [Bernd Schubert]. (This was asked for but later deemed unnecessary with the open-by-handle capability available and caused disagreement as to whether it's a security hole or not). (10) Extra coherency data may be useful in making backups [Andreas Dilger]. (No particular data were offered, but things like last backup timestamp, the data version number and the DOS archive bit would come into this category). (11) Allow the filesystem to indicate what it can/cannot provide: A filesystem can now say it doesn't support a standard stat feature if that isn't available, so if, for instance, inode numbers or UIDs don't exist or are fabricated locally... (This requires a separate system call - I have an fsinfo() call idea for this). (12) Store a 16-byte volume ID in the superblock that can be returned in struct xstat [Steve French]. (Deferred to fsinfo). (13) Include granularity fields in the time data to indicate the granularity of each of the times (NFSv4 time_delta) [Steve French]. (Deferred to fsinfo). (14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags. Note that the Linux IOC flags are a mess and filesystems such as Ext4 define flags that aren't in linux/fs.h, so translation in the kernel may be a necessity (or, possibly, we provide the filesystem type too). (Some attributes are made available in stx_attributes, but the general feeling was that the IOC flags were to ext[234]-specific and shouldn't be exposed through statx this way). (15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer, Michael Kerrisk]. (Deferred, probably to fsinfo. Finding out if there's an ACL or seclabal might require extra filesystem operations). (16) Femtosecond-resolution timestamps [Dave Chinner]. (A __reserved field has been left in the statx_timestamp struct for this - if there proves to be a need). (17) A set multiple attributes syscall to go with this. =============== NEW SYSTEM CALL =============== The new system call is: int ret = statx(int dfd, const char *filename, unsigned int flags, unsigned int mask, struct statx *buffer); The dfd, filename and flags parameters indicate the file to query, in a similar way to fstatat(). There is no equivalent of lstat() as that can be emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is also no equivalent of fstat() as that can be emulated by passing a NULL filename to statx() with the fd of interest in dfd. Whether or not statx() synchronises the attributes with the backing store can be controlled by OR'ing a value into the flags argument (this typically only affects network filesystems): (1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this respect. (2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise its attributes with the server - which might require data writeback to occur to get the timestamps correct. (3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a network filesystem. The resulting values should be considered approximate. mask is a bitmask indicating the fields in struct statx that are of interest to the caller. The user should set this to STATX_BASIC_STATS to get the basic set returned by stat(). It should be noted that asking for more information may entail extra I/O operations. buffer points to the destination for the data. This must be 256 bytes in size. ====================== MAIN ATTRIBUTES RECORD ====================== The following structures are defined in which to return the main attribute set: struct statx_timestamp { __s64 tv_sec; __s32 tv_nsec; __s32 __reserved; }; struct statx { __u32 stx_mask; __u32 stx_blksize; __u64 stx_attributes; __u32 stx_nlink; __u32 stx_uid; __u32 stx_gid; __u16 stx_mode; __u16 __spare0[1]; __u64 stx_ino; __u64 stx_size; __u64 stx_blocks; __u64 __spare1[1]; struct statx_timestamp stx_atime; struct statx_timestamp stx_btime; struct statx_timestamp stx_ctime; struct statx_timestamp stx_mtime; __u32 stx_rdev_major; __u32 stx_rdev_minor; __u32 stx_dev_major; __u32 stx_dev_minor; __u64 __spare2[14]; }; The defined bits in request_mask and stx_mask are: STATX_TYPE Want/got stx_mode & S_IFMT STATX_MODE Want/got stx_mode & ~S_IFMT STATX_NLINK Want/got stx_nlink STATX_UID Want/got stx_uid STATX_GID Want/got stx_gid STATX_ATIME Want/got stx_atime{,_ns} STATX_MTIME Want/got stx_mtime{,_ns} STATX_CTIME Want/got stx_ctime{,_ns} STATX_INO Want/got stx_ino STATX_SIZE Want/got stx_size STATX_BLOCKS Want/got stx_blocks STATX_BASIC_STATS [The stuff in the normal stat struct] STATX_BTIME Want/got stx_btime{,_ns} STATX_ALL [All currently available stuff] stx_btime is the file creation time, stx_mask is a bitmask indicating the data provided and __spares*[] are where as-yet undefined fields can be placed. Time fields are structures with separate seconds and nanoseconds fields plus a reserved field in case we want to add even finer resolution. Note that times will be negative if before 1970; in such a case, the nanosecond fields will also be negative if not zero. The bits defined in the stx_attributes field convey information about a file, how it is accessed, where it is and what it does. The following attributes map to FS_*_FL flags and are the same numerical value: STATX_ATTR_COMPRESSED File is compressed by the fs STATX_ATTR_IMMUTABLE File is marked immutable STATX_ATTR_APPEND File is append-only STATX_ATTR_NODUMP File is not to be dumped STATX_ATTR_ENCRYPTED File requires key to decrypt in fs Within the kernel, the supported flags are listed by: KSTAT_ATTR_FS_IOC_FLAGS [Are any other IOC flags of sufficient general interest to be exposed through this interface?] New flags include: STATX_ATTR_AUTOMOUNT Object is an automount trigger These are for the use of GUI tools that might want to mark files specially, depending on what they are. Fields in struct statx come in a number of classes: (0) stx_dev_*, stx_blksize. These are local system information and are always available. (1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino, stx_size, stx_blocks. These will be returned whether the caller asks for them or not. The corresponding bits in stx_mask will be set to indicate whether they actually have valid values. If the caller didn't ask for them, then they may be approximated. For example, NFS won't waste any time updating them from the server, unless as a byproduct of updating something requested. If the values don't actually exist for the underlying object (such as UID or GID on a DOS file), then the bit won't be set in the stx_mask, even if the caller asked for the value. In such a case, the returned value will be a fabrication. Note that there are instances where the type might not be valid, for instance Windows reparse points. (2) stx_rdev_*. This will be set only if stx_mode indicates we're looking at a blockdev or a chardev, otherwise will be 0. (3) stx_btime. Similar to (1), except this will be set to 0 if it doesn't exist. ======= TESTING ======= The following test program can be used to test the statx system call: samples/statx/test-statx.c Just compile and run, passing it paths to the files you want to examine. The file is built automatically if CONFIG_SAMPLES is enabled. Here's some example output. Firstly, an NFS directory that crosses to another FSID. Note that the AUTOMOUNT attribute is set because transiting this directory will cause d_automount to be invoked by the VFS. [root@andromeda ~]# /tmp/test-statx -A /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:26 Inode: 1703937 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------) Secondly, the result of automounting on that directory. [root@andromeda ~]# /tmp/test-statx /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:27 Inode: 2 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-01-31 16:46:22 +00:00
statx: Add a system call to make enhanced file info available Add a system call to make extended file information available, including file creation and some attribute flags where available through the underlying filesystem. The getattr inode operation is altered to take two additional arguments: a u32 request_mask and an unsigned int flags that indicate the synchronisation mode. This change is propagated to the vfs_getattr*() function. Functions like vfs_stat() are now inline wrappers around new functions vfs_statx() and vfs_statx_fd() to reduce stack usage. ======== OVERVIEW ======== The idea was initially proposed as a set of xattrs that could be retrieved with getxattr(), but the general preference proved to be for a new syscall with an extended stat structure. A number of requests were gathered for features to be included. The following have been included: (1) Make the fields a consistent size on all arches and make them large. (2) Spare space, request flags and information flags are provided for future expansion. (3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an __s64). (4) Creation time: The SMB protocol carries the creation time, which could be exported by Samba, which will in turn help CIFS make use of FS-Cache as that can be used for coherency data (stx_btime). This is also specified in NFSv4 as a recommended attribute and could be exported by NFSD [Steve French]. (5) Lightweight stat: Ask for just those details of interest, and allow a netfs (such as NFS) to approximate anything not of interest, possibly without going to the server [Trond Myklebust, Ulrich Drepper, Andreas Dilger] (AT_STATX_DONT_SYNC). (6) Heavyweight stat: Force a netfs to go to the server, even if it thinks its cached attributes are up to date [Trond Myklebust] (AT_STATX_FORCE_SYNC). And the following have been left out for future extension: (7) Data version number: Could be used by userspace NFS servers [Aneesh Kumar]. Can also be used to modify fill_post_wcc() in NFSD which retrieves i_version directly, but has just called vfs_getattr(). It could get it from the kstat struct if it used vfs_xgetattr() instead. (There's disagreement on the exact semantics of a single field, since not all filesystems do this the same way). (8) BSD stat compatibility: Including more fields from the BSD stat such as creation time (st_btime) and inode generation number (st_gen) [Jeremy Allison, Bernd Schubert]. (9) Inode generation number: Useful for FUSE and userspace NFS servers [Bernd Schubert]. (This was asked for but later deemed unnecessary with the open-by-handle capability available and caused disagreement as to whether it's a security hole or not). (10) Extra coherency data may be useful in making backups [Andreas Dilger]. (No particular data were offered, but things like last backup timestamp, the data version number and the DOS archive bit would come into this category). (11) Allow the filesystem to indicate what it can/cannot provide: A filesystem can now say it doesn't support a standard stat feature if that isn't available, so if, for instance, inode numbers or UIDs don't exist or are fabricated locally... (This requires a separate system call - I have an fsinfo() call idea for this). (12) Store a 16-byte volume ID in the superblock that can be returned in struct xstat [Steve French]. (Deferred to fsinfo). (13) Include granularity fields in the time data to indicate the granularity of each of the times (NFSv4 time_delta) [Steve French]. (Deferred to fsinfo). (14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags. Note that the Linux IOC flags are a mess and filesystems such as Ext4 define flags that aren't in linux/fs.h, so translation in the kernel may be a necessity (or, possibly, we provide the filesystem type too). (Some attributes are made available in stx_attributes, but the general feeling was that the IOC flags were to ext[234]-specific and shouldn't be exposed through statx this way). (15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer, Michael Kerrisk]. (Deferred, probably to fsinfo. Finding out if there's an ACL or seclabal might require extra filesystem operations). (16) Femtosecond-resolution timestamps [Dave Chinner]. (A __reserved field has been left in the statx_timestamp struct for this - if there proves to be a need). (17) A set multiple attributes syscall to go with this. =============== NEW SYSTEM CALL =============== The new system call is: int ret = statx(int dfd, const char *filename, unsigned int flags, unsigned int mask, struct statx *buffer); The dfd, filename and flags parameters indicate the file to query, in a similar way to fstatat(). There is no equivalent of lstat() as that can be emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is also no equivalent of fstat() as that can be emulated by passing a NULL filename to statx() with the fd of interest in dfd. Whether or not statx() synchronises the attributes with the backing store can be controlled by OR'ing a value into the flags argument (this typically only affects network filesystems): (1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this respect. (2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise its attributes with the server - which might require data writeback to occur to get the timestamps correct. (3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a network filesystem. The resulting values should be considered approximate. mask is a bitmask indicating the fields in struct statx that are of interest to the caller. The user should set this to STATX_BASIC_STATS to get the basic set returned by stat(). It should be noted that asking for more information may entail extra I/O operations. buffer points to the destination for the data. This must be 256 bytes in size. ====================== MAIN ATTRIBUTES RECORD ====================== The following structures are defined in which to return the main attribute set: struct statx_timestamp { __s64 tv_sec; __s32 tv_nsec; __s32 __reserved; }; struct statx { __u32 stx_mask; __u32 stx_blksize; __u64 stx_attributes; __u32 stx_nlink; __u32 stx_uid; __u32 stx_gid; __u16 stx_mode; __u16 __spare0[1]; __u64 stx_ino; __u64 stx_size; __u64 stx_blocks; __u64 __spare1[1]; struct statx_timestamp stx_atime; struct statx_timestamp stx_btime; struct statx_timestamp stx_ctime; struct statx_timestamp stx_mtime; __u32 stx_rdev_major; __u32 stx_rdev_minor; __u32 stx_dev_major; __u32 stx_dev_minor; __u64 __spare2[14]; }; The defined bits in request_mask and stx_mask are: STATX_TYPE Want/got stx_mode & S_IFMT STATX_MODE Want/got stx_mode & ~S_IFMT STATX_NLINK Want/got stx_nlink STATX_UID Want/got stx_uid STATX_GID Want/got stx_gid STATX_ATIME Want/got stx_atime{,_ns} STATX_MTIME Want/got stx_mtime{,_ns} STATX_CTIME Want/got stx_ctime{,_ns} STATX_INO Want/got stx_ino STATX_SIZE Want/got stx_size STATX_BLOCKS Want/got stx_blocks STATX_BASIC_STATS [The stuff in the normal stat struct] STATX_BTIME Want/got stx_btime{,_ns} STATX_ALL [All currently available stuff] stx_btime is the file creation time, stx_mask is a bitmask indicating the data provided and __spares*[] are where as-yet undefined fields can be placed. Time fields are structures with separate seconds and nanoseconds fields plus a reserved field in case we want to add even finer resolution. Note that times will be negative if before 1970; in such a case, the nanosecond fields will also be negative if not zero. The bits defined in the stx_attributes field convey information about a file, how it is accessed, where it is and what it does. The following attributes map to FS_*_FL flags and are the same numerical value: STATX_ATTR_COMPRESSED File is compressed by the fs STATX_ATTR_IMMUTABLE File is marked immutable STATX_ATTR_APPEND File is append-only STATX_ATTR_NODUMP File is not to be dumped STATX_ATTR_ENCRYPTED File requires key to decrypt in fs Within the kernel, the supported flags are listed by: KSTAT_ATTR_FS_IOC_FLAGS [Are any other IOC flags of sufficient general interest to be exposed through this interface?] New flags include: STATX_ATTR_AUTOMOUNT Object is an automount trigger These are for the use of GUI tools that might want to mark files specially, depending on what they are. Fields in struct statx come in a number of classes: (0) stx_dev_*, stx_blksize. These are local system information and are always available. (1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino, stx_size, stx_blocks. These will be returned whether the caller asks for them or not. The corresponding bits in stx_mask will be set to indicate whether they actually have valid values. If the caller didn't ask for them, then they may be approximated. For example, NFS won't waste any time updating them from the server, unless as a byproduct of updating something requested. If the values don't actually exist for the underlying object (such as UID or GID on a DOS file), then the bit won't be set in the stx_mask, even if the caller asked for the value. In such a case, the returned value will be a fabrication. Note that there are instances where the type might not be valid, for instance Windows reparse points. (2) stx_rdev_*. This will be set only if stx_mode indicates we're looking at a blockdev or a chardev, otherwise will be 0. (3) stx_btime. Similar to (1), except this will be set to 0 if it doesn't exist. ======= TESTING ======= The following test program can be used to test the statx system call: samples/statx/test-statx.c Just compile and run, passing it paths to the files you want to examine. The file is built automatically if CONFIG_SAMPLES is enabled. Here's some example output. Firstly, an NFS directory that crosses to another FSID. Note that the AUTOMOUNT attribute is set because transiting this directory will cause d_automount to be invoked by the VFS. [root@andromeda ~]# /tmp/test-statx -A /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:26 Inode: 1703937 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------) Secondly, the result of automounting on that directory. [root@andromeda ~]# /tmp/test-statx /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:27 Inode: 2 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-01-31 16:46:22 +00:00
statx: Add a system call to make enhanced file info available Add a system call to make extended file information available, including file creation and some attribute flags where available through the underlying filesystem. The getattr inode operation is altered to take two additional arguments: a u32 request_mask and an unsigned int flags that indicate the synchronisation mode. This change is propagated to the vfs_getattr*() function. Functions like vfs_stat() are now inline wrappers around new functions vfs_statx() and vfs_statx_fd() to reduce stack usage. ======== OVERVIEW ======== The idea was initially proposed as a set of xattrs that could be retrieved with getxattr(), but the general preference proved to be for a new syscall with an extended stat structure. A number of requests were gathered for features to be included. The following have been included: (1) Make the fields a consistent size on all arches and make them large. (2) Spare space, request flags and information flags are provided for future expansion. (3) Better support for the y2038 problem [Arnd Bergmann] (tv_sec is an __s64). (4) Creation time: The SMB protocol carries the creation time, which could be exported by Samba, which will in turn help CIFS make use of FS-Cache as that can be used for coherency data (stx_btime). This is also specified in NFSv4 as a recommended attribute and could be exported by NFSD [Steve French]. (5) Lightweight stat: Ask for just those details of interest, and allow a netfs (such as NFS) to approximate anything not of interest, possibly without going to the server [Trond Myklebust, Ulrich Drepper, Andreas Dilger] (AT_STATX_DONT_SYNC). (6) Heavyweight stat: Force a netfs to go to the server, even if it thinks its cached attributes are up to date [Trond Myklebust] (AT_STATX_FORCE_SYNC). And the following have been left out for future extension: (7) Data version number: Could be used by userspace NFS servers [Aneesh Kumar]. Can also be used to modify fill_post_wcc() in NFSD which retrieves i_version directly, but has just called vfs_getattr(). It could get it from the kstat struct if it used vfs_xgetattr() instead. (There's disagreement on the exact semantics of a single field, since not all filesystems do this the same way). (8) BSD stat compatibility: Including more fields from the BSD stat such as creation time (st_btime) and inode generation number (st_gen) [Jeremy Allison, Bernd Schubert]. (9) Inode generation number: Useful for FUSE and userspace NFS servers [Bernd Schubert]. (This was asked for but later deemed unnecessary with the open-by-handle capability available and caused disagreement as to whether it's a security hole or not). (10) Extra coherency data may be useful in making backups [Andreas Dilger]. (No particular data were offered, but things like last backup timestamp, the data version number and the DOS archive bit would come into this category). (11) Allow the filesystem to indicate what it can/cannot provide: A filesystem can now say it doesn't support a standard stat feature if that isn't available, so if, for instance, inode numbers or UIDs don't exist or are fabricated locally... (This requires a separate system call - I have an fsinfo() call idea for this). (12) Store a 16-byte volume ID in the superblock that can be returned in struct xstat [Steve French]. (Deferred to fsinfo). (13) Include granularity fields in the time data to indicate the granularity of each of the times (NFSv4 time_delta) [Steve French]. (Deferred to fsinfo). (14) FS_IOC_GETFLAGS value. These could be translated to BSD's st_flags. Note that the Linux IOC flags are a mess and filesystems such as Ext4 define flags that aren't in linux/fs.h, so translation in the kernel may be a necessity (or, possibly, we provide the filesystem type too). (Some attributes are made available in stx_attributes, but the general feeling was that the IOC flags were to ext[234]-specific and shouldn't be exposed through statx this way). (15) Mask of features available on file (eg: ACLs, seclabel) [Brad Boyer, Michael Kerrisk]. (Deferred, probably to fsinfo. Finding out if there's an ACL or seclabal might require extra filesystem operations). (16) Femtosecond-resolution timestamps [Dave Chinner]. (A __reserved field has been left in the statx_timestamp struct for this - if there proves to be a need). (17) A set multiple attributes syscall to go with this. =============== NEW SYSTEM CALL =============== The new system call is: int ret = statx(int dfd, const char *filename, unsigned int flags, unsigned int mask, struct statx *buffer); The dfd, filename and flags parameters indicate the file to query, in a similar way to fstatat(). There is no equivalent of lstat() as that can be emulated with statx() by passing AT_SYMLINK_NOFOLLOW in flags. There is also no equivalent of fstat() as that can be emulated by passing a NULL filename to statx() with the fd of interest in dfd. Whether or not statx() synchronises the attributes with the backing store can be controlled by OR'ing a value into the flags argument (this typically only affects network filesystems): (1) AT_STATX_SYNC_AS_STAT tells statx() to behave as stat() does in this respect. (2) AT_STATX_FORCE_SYNC will require a network filesystem to synchronise its attributes with the server - which might require data writeback to occur to get the timestamps correct. (3) AT_STATX_DONT_SYNC will suppress synchronisation with the server in a network filesystem. The resulting values should be considered approximate. mask is a bitmask indicating the fields in struct statx that are of interest to the caller. The user should set this to STATX_BASIC_STATS to get the basic set returned by stat(). It should be noted that asking for more information may entail extra I/O operations. buffer points to the destination for the data. This must be 256 bytes in size. ====================== MAIN ATTRIBUTES RECORD ====================== The following structures are defined in which to return the main attribute set: struct statx_timestamp { __s64 tv_sec; __s32 tv_nsec; __s32 __reserved; }; struct statx { __u32 stx_mask; __u32 stx_blksize; __u64 stx_attributes; __u32 stx_nlink; __u32 stx_uid; __u32 stx_gid; __u16 stx_mode; __u16 __spare0[1]; __u64 stx_ino; __u64 stx_size; __u64 stx_blocks; __u64 __spare1[1]; struct statx_timestamp stx_atime; struct statx_timestamp stx_btime; struct statx_timestamp stx_ctime; struct statx_timestamp stx_mtime; __u32 stx_rdev_major; __u32 stx_rdev_minor; __u32 stx_dev_major; __u32 stx_dev_minor; __u64 __spare2[14]; }; The defined bits in request_mask and stx_mask are: STATX_TYPE Want/got stx_mode & S_IFMT STATX_MODE Want/got stx_mode & ~S_IFMT STATX_NLINK Want/got stx_nlink STATX_UID Want/got stx_uid STATX_GID Want/got stx_gid STATX_ATIME Want/got stx_atime{,_ns} STATX_MTIME Want/got stx_mtime{,_ns} STATX_CTIME Want/got stx_ctime{,_ns} STATX_INO Want/got stx_ino STATX_SIZE Want/got stx_size STATX_BLOCKS Want/got stx_blocks STATX_BASIC_STATS [The stuff in the normal stat struct] STATX_BTIME Want/got stx_btime{,_ns} STATX_ALL [All currently available stuff] stx_btime is the file creation time, stx_mask is a bitmask indicating the data provided and __spares*[] are where as-yet undefined fields can be placed. Time fields are structures with separate seconds and nanoseconds fields plus a reserved field in case we want to add even finer resolution. Note that times will be negative if before 1970; in such a case, the nanosecond fields will also be negative if not zero. The bits defined in the stx_attributes field convey information about a file, how it is accessed, where it is and what it does. The following attributes map to FS_*_FL flags and are the same numerical value: STATX_ATTR_COMPRESSED File is compressed by the fs STATX_ATTR_IMMUTABLE File is marked immutable STATX_ATTR_APPEND File is append-only STATX_ATTR_NODUMP File is not to be dumped STATX_ATTR_ENCRYPTED File requires key to decrypt in fs Within the kernel, the supported flags are listed by: KSTAT_ATTR_FS_IOC_FLAGS [Are any other IOC flags of sufficient general interest to be exposed through this interface?] New flags include: STATX_ATTR_AUTOMOUNT Object is an automount trigger These are for the use of GUI tools that might want to mark files specially, depending on what they are. Fields in struct statx come in a number of classes: (0) stx_dev_*, stx_blksize. These are local system information and are always available. (1) stx_mode, stx_nlinks, stx_uid, stx_gid, stx_[amc]time, stx_ino, stx_size, stx_blocks. These will be returned whether the caller asks for them or not. The corresponding bits in stx_mask will be set to indicate whether they actually have valid values. If the caller didn't ask for them, then they may be approximated. For example, NFS won't waste any time updating them from the server, unless as a byproduct of updating something requested. If the values don't actually exist for the underlying object (such as UID or GID on a DOS file), then the bit won't be set in the stx_mask, even if the caller asked for the value. In such a case, the returned value will be a fabrication. Note that there are instances where the type might not be valid, for instance Windows reparse points. (2) stx_rdev_*. This will be set only if stx_mode indicates we're looking at a blockdev or a chardev, otherwise will be 0. (3) stx_btime. Similar to (1), except this will be set to 0 if it doesn't exist. ======= TESTING ======= The following test program can be used to test the statx system call: samples/statx/test-statx.c Just compile and run, passing it paths to the files you want to examine. The file is built automatically if CONFIG_SAMPLES is enabled. Here's some example output. Firstly, an NFS directory that crosses to another FSID. Note that the AUTOMOUNT attribute is set because transiting this directory will cause d_automount to be invoked by the VFS. [root@andromeda ~]# /tmp/test-statx -A /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:26 Inode: 1703937 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Attributes: 0000000000001000 (-------- -------- -------- -------- -------- -------- ---m---- --------) Secondly, the result of automounting on that directory. [root@andromeda ~]# /tmp/test-statx /warthog/data statx(/warthog/data) = 0 results=7ff Size: 4096 Blocks: 8 IO Block: 1048576 directory Device: 00:27 Inode: 2 Links: 125 Access: (3777/drwxrwxrwx) Uid: 0 Gid: 4041 Access: 2016-11-24 09:02:12.219699527+0000 Modify: 2016-11-17 10:44:36.225653653+0000 Change: 2016-11-17 10:44:36.225653653+0000 Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-01-31 16:46:22 +00:00