linux/fs/buffer.c

3255 lines
86 KiB

[PATCH] spinlock consolidation This patch (written by me and also containing many suggestions of Arjan van de Ven) does a major cleanup of the spinlock code. It does the following things: - consolidates and enhances the spinlock/rwlock debugging code - simplifies the asm/spinlock.h files - encapsulates the raw spinlock type and moves generic spinlock features (such as ->break_lock) into the generic code. - cleans up the spinlock code hierarchy to get rid of the spaghetti. Most notably there's now only a single variant of the debugging code, located in lib/spinlock_debug.c. (previously we had one SMP debugging variant per architecture, plus a separate generic one for UP builds) Also, i've enhanced the rwlock debugging facility, it will now track write-owners. There is new spinlock-owner/CPU-tracking on SMP builds too. All locks have lockup detection now, which will work for both soft and hard spin/rwlock lockups. The arch-level include files now only contain the minimally necessary subset of the spinlock code - all the rest that can be generalized now lives in the generic headers: include/asm-i386/spinlock_types.h | 16 include/asm-x86_64/spinlock_types.h | 16 I have also split up the various spinlock variants into separate files, making it easier to see which does what. The new layout is: SMP | UP ----------------------------|----------------------------------- asm/spinlock_types_smp.h | linux/spinlock_types_up.h linux/spinlock_types.h | linux/spinlock_types.h asm/spinlock_smp.h | linux/spinlock_up.h linux/spinlock_api_smp.h | linux/spinlock_api_up.h linux/spinlock.h | linux/spinlock.h /* * here's the role of the various spinlock/rwlock related include files: * * on SMP builds: * * asm/spinlock_types.h: contains the raw_spinlock_t/raw_rwlock_t and the * initializers * * linux/spinlock_types.h: * defines the generic type and initializers * * asm/spinlock.h: contains the __raw_spin_*()/etc. lowlevel * implementations, mostly inline assembly code * * (also included on UP-debug builds:) * * linux/spinlock_api_smp.h: * contains the prototypes for the _spin_*() APIs. * * linux/spinlock.h: builds the final spin_*() APIs. * * on UP builds: * * linux/spinlock_type_up.h: * contains the generic, simplified UP spinlock type. * (which is an empty structure on non-debug builds) * * linux/spinlock_types.h: * defines the generic type and initializers * * linux/spinlock_up.h: * contains the __raw_spin_*()/etc. version of UP * builds. (which are NOPs on non-debug, non-preempt * builds) * * (included on UP-non-debug builds:) * * linux/spinlock_api_up.h: * builds the _spin_*() APIs. * * linux/spinlock.h: builds the final spin_*() APIs. */ All SMP and UP architectures are converted by this patch. arm, i386, ia64, ppc, ppc64, s390/s390x, x64 was build-tested via crosscompilers. m32r, mips, sh, sparc, have not been tested yet, but should be mostly fine. From: Grant Grundler <grundler@parisc-linux.org> Booted and lightly tested on a500-44 (64-bit, SMP kernel, dual CPU). Builds 32-bit SMP kernel (not booted or tested). I did not try to build non-SMP kernels. That should be trivial to fix up later if necessary. I converted bit ops atomic_hash lock to raw_spinlock_t. Doing so avoids some ugly nesting of linux/*.h and asm/*.h files. Those particular locks are well tested and contained entirely inside arch specific code. I do NOT expect any new issues to arise with them. If someone does ever need to use debug/metrics with them, then they will need to unravel this hairball between spinlocks, atomic ops, and bit ops that exist only because parisc has exactly one atomic instruction: LDCW (load and clear word). From: "Luck, Tony" <tony.luck@intel.com> ia64 fix Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjanv@infradead.org> Signed-off-by: Grant Grundler <grundler@parisc-linux.org> Cc: Matthew Wilcox <willy@debian.org> Signed-off-by: Hirokazu Takata <takata@linux-m32r.org> Signed-off-by: Mikael Pettersson <mikpe@csd.uu.se> Signed-off-by: Benoit Boissinot <benoit.boissinot@ens-lyon.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-10 00:25:56 -07:00
[PATCH] buffer: memorder fix unlock_buffer(), like unlock_page(), must not clear the lock without ensuring that the critical section is closed. Mingming later sent the same patch, saying: We are running SDET benchmark and saw double free issue for ext3 extended attributes block, which complains the same xattr block already being freed (in ext3_xattr_release_block()). The problem could also been triggered by multiple threads loop untar/rm a kernel tree. The race is caused by missing a memory barrier at unlock_buffer() before the lock bit being cleared, resulting in possible concurrent h_refcounter update. That causes a reference counter leak, then later leads to the double free that we have seen. Inside unlock_buffer(), there is a memory barrier is placed *after* the lock bit is being cleared, however, there is no memory barrier *before* the bit is cleared. On some arch the h_refcount update instruction and the clear bit instruction could be reordered, thus leave the critical section re-entered. The race is like this: For example, if the h_refcount is initialized as 1, cpu 0: cpu1 -------------------------------------- ----------------------------------- lock_buffer() /* test_and_set_bit */ clear_buffer_locked(bh); lock_buffer() /* test_and_set_bit */ h_refcount = h_refcount+1; /* = 2*/ h_refcount = h_refcount + 1; /*= 2 */ clear_buffer_locked(bh); .... ...... We lost a h_refcount here. We need a memory barrier before the buffer head lock bit being cleared to force the order of the two writes. Please apply. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Mingming Cao <cmm@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-10 01:46:22 -08:00
[PATCH] mm: split page table lock Christoph Lameter demonstrated very poor scalability on the SGI 512-way, with a many-threaded application which concurrently initializes different parts of a large anonymous area. This patch corrects that, by using a separate spinlock per page table page, to guard the page table entries in that page, instead of using the mm's single page_table_lock. (But even then, page_table_lock is still used to guard page table allocation, and anon_vma allocation.) In this implementation, the spinlock is tucked inside the struct page of the page table page: with a BUILD_BUG_ON in case it overflows - which it would in the case of 32-bit PA-RISC with spinlock debugging enabled. Splitting the lock is not quite for free: another cacheline access. Ideally, I suppose we would use split ptlock only for multi-threaded processes on multi-cpu machines; but deciding that dynamically would have its own costs. So for now enable it by config, at some number of cpus - since the Kconfig language doesn't support inequalities, let preprocessor compare that with NR_CPUS. But I don't think it's worth being user-configurable: for good testing of both split and unsplit configs, split now at 4 cpus, and perhaps change that to 8 later. There is a benefit even for singly threaded processes: kswapd can be attacking one part of the mm while another part is busy faulting. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29 18:16:40 -07:00
Lumpy Reclaim V4 When we are out of memory of a suitable size we enter reclaim. The current reclaim algorithm targets pages in LRU order, which is great for fairness at order-0 but highly unsuitable if you desire pages at higher orders. To get pages of higher order we must shoot down a very high proportion of memory; >95% in a lot of cases. This patch set adds a lumpy reclaim algorithm to the allocator. It targets groups of pages at the specified order anchored at the end of the active and inactive lists. This encourages groups of pages at the requested orders to move from active to inactive, and active to free lists. This behaviour is only triggered out of direct reclaim when higher order pages have been requested. This patch set is particularly effective when utilised with an anti-fragmentation scheme which groups pages of similar reclaimability together. This patch set is based on Peter Zijlstra's lumpy reclaim V2 patch which forms the foundation. Credit to Mel Gorman for sanitity checking. Mel said: The patches have an application with hugepage pool resizing. When lumpy-reclaim is used used with ZONE_MOVABLE, the hugepages pool can be resized with greater reliability. Testing on a desktop machine with 2GB of RAM showed that growing the hugepage pool with ZONE_MOVABLE on it's own was very slow as the success rate was quite low. Without lumpy-reclaim, each attempt to grow the pool by 100 pages would yield 1 or 2 hugepages. With lumpy-reclaim, getting 40 to 70 hugepages on each attempt was typical. [akpm@osdl.org: ia64 pfn_to_nid fixes and loop cleanup] [bunk@stusta.de: static declarations for internal functions] [a.p.zijlstra@chello.nl: initial lumpy V2 implementation] Signed-off-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: Bob Picco <bob.picco@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17 04:03:16 -07:00
Add __GFP_MOVABLE for callers to flag allocations from high memory that may be migrated It is often known at allocation time whether a page may be migrated or not. This patch adds a flag called __GFP_MOVABLE and a new mask called GFP_HIGH_MOVABLE. Allocations using the __GFP_MOVABLE can be either migrated using the page migration mechanism or reclaimed by syncing with backing storage and discarding. An API function very similar to alloc_zeroed_user_highpage() is added for __GFP_MOVABLE allocations called alloc_zeroed_user_highpage_movable(). The flags used by alloc_zeroed_user_highpage() are not changed because it would change the semantics of an existing API. After this patch is applied there are no in-kernel users of alloc_zeroed_user_highpage() so it probably should be marked deprecated if this patch is merged. Note that this patch includes a minor cleanup to the use of __GFP_ZERO in shmem.c to keep all flag modifications to inode->mapping in the shmem_dir_alloc() helper function. This clean-up suggestion is courtesy of Hugh Dickens. Additional credit goes to Christoph Lameter and Linus Torvalds for shaping the concept. Credit to Hugh Dickens for catching issues with shmem swap vector and ramfs allocations. [akpm@linux-foundation.org: build fix] [hugh@veritas.com: __GFP_ZERO cleanup] Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17 04:03:05 -07:00
[PATCH] fix possible PAGE_CACHE_SHIFT overflows We've had two instances recently of overflows when doing 64_bit_value = (32_bit_value << PAGE_CACHE_SHIFT) I did a tree-wide grep of `<<.*PAGE_CACHE_SHIFT' and this is the result. - afs_rxfs_fetch_descriptor.offset is of type off_t, which seems broken. - jfs and jffs are limited to 4GB anyway. - reiserfs map_block_for_writepage() takes an unsigned long for the block - it should take sector_t. (It'll fail for huge filesystems with blocksize<PAGE_CACHE_SIZE) - cramfs_read() needs to use sector_t (I think cramsfs is busted on large filesystems anyway) - affs is limited in file size anyway. - I generally didn't fix 32-bit overflows in directory operations. - arm's __flush_dcache_page() is peculiar. What if the page lies beyond 4G? - gss_wrap_req_priv() needs checking (snd_buf->page_base) Cc: Oleg Drokin <green@linuxhacker.ru> Cc: David Howells <dhowells@redhat.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: <reiserfs-dev@namesys.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Anton Altaparmakov <aia21@cantab.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: <linux-fsdevel@vger.kernel.org> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: Neil Brown <neilb@cse.unsw.edu.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 01:03:05 -08:00
fs: fix nobh error handling nobh mode error handling is not just pretty slack, it's wrong. One cannot zero out the whole page to ensure new blocks are zeroed, because it just brings the whole page "uptodate" with zeroes even if that may not be the correct uptodate data. Also, other parts of the page may already contain dirty data which would get lost by zeroing it out. Thirdly, the writeback of zeroes to the new blocks will also erase existing blocks. All these conditions are pagecache and/or filesystem corruption. The problem comes about because we didn't keep track of which buffers actually are new or old. However it is not enough just to keep only this state, because at the point we start dirtying parts of the page (new blocks, with zeroes), the handling of IO errors becomes impossible without buffers because the page may only be partially uptodate, in which case the page flags allone cannot capture the state of the parts of the page. So allocate all buffers for the page upfront, but leave them unattached so that they don't pick up any other references and can be freed when we're done. If the error path is hit, then zero the new buffers as the regular buffer path does, then attach the buffers to the page so that it can actually be written out correctly and be subject to the normal IO error handling paths. As an upshot, we save 1K of kernel stack on ia64 or powerpc 64K page systems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 01:24:48 -07:00
fs: fix nobh error handling nobh mode error handling is not just pretty slack, it's wrong. One cannot zero out the whole page to ensure new blocks are zeroed, because it just brings the whole page "uptodate" with zeroes even if that may not be the correct uptodate data. Also, other parts of the page may already contain dirty data which would get lost by zeroing it out. Thirdly, the writeback of zeroes to the new blocks will also erase existing blocks. All these conditions are pagecache and/or filesystem corruption. The problem comes about because we didn't keep track of which buffers actually are new or old. However it is not enough just to keep only this state, because at the point we start dirtying parts of the page (new blocks, with zeroes), the handling of IO errors becomes impossible without buffers because the page may only be partially uptodate, in which case the page flags allone cannot capture the state of the parts of the page. So allocate all buffers for the page upfront, but leave them unattached so that they don't pick up any other references and can be freed when we're done. If the error path is hit, then zero the new buffers as the regular buffer path does, then attach the buffers to the page so that it can actually be written out correctly and be subject to the normal IO error handling paths. As an upshot, we save 1K of kernel stack on ia64 or powerpc 64K page systems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 01:24:48 -07:00
fs: fix nobh error handling nobh mode error handling is not just pretty slack, it's wrong. One cannot zero out the whole page to ensure new blocks are zeroed, because it just brings the whole page "uptodate" with zeroes even if that may not be the correct uptodate data. Also, other parts of the page may already contain dirty data which would get lost by zeroing it out. Thirdly, the writeback of zeroes to the new blocks will also erase existing blocks. All these conditions are pagecache and/or filesystem corruption. The problem comes about because we didn't keep track of which buffers actually are new or old. However it is not enough just to keep only this state, because at the point we start dirtying parts of the page (new blocks, with zeroes), the handling of IO errors becomes impossible without buffers because the page may only be partially uptodate, in which case the page flags allone cannot capture the state of the parts of the page. So allocate all buffers for the page upfront, but leave them unattached so that they don't pick up any other references and can be freed when we're done. If the error path is hit, then zero the new buffers as the regular buffer path does, then attach the buffers to the page so that it can actually be written out correctly and be subject to the normal IO error handling paths. As an upshot, we save 1K of kernel stack on ia64 or powerpc 64K page systems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 01:24:48 -07:00
fs: fix nobh error handling nobh mode error handling is not just pretty slack, it's wrong. One cannot zero out the whole page to ensure new blocks are zeroed, because it just brings the whole page "uptodate" with zeroes even if that may not be the correct uptodate data. Also, other parts of the page may already contain dirty data which would get lost by zeroing it out. Thirdly, the writeback of zeroes to the new blocks will also erase existing blocks. All these conditions are pagecache and/or filesystem corruption. The problem comes about because we didn't keep track of which buffers actually are new or old. However it is not enough just to keep only this state, because at the point we start dirtying parts of the page (new blocks, with zeroes), the handling of IO errors becomes impossible without buffers because the page may only be partially uptodate, in which case the page flags allone cannot capture the state of the parts of the page. So allocate all buffers for the page upfront, but leave them unattached so that they don't pick up any other references and can be freed when we're done. If the error path is hit, then zero the new buffers as the regular buffer path does, then attach the buffers to the page so that it can actually be written out correctly and be subject to the normal IO error handling paths. As an upshot, we save 1K of kernel stack on ia64 or powerpc 64K page systems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 01:24:48 -07:00
fs: fix nobh error handling nobh mode error handling is not just pretty slack, it's wrong. One cannot zero out the whole page to ensure new blocks are zeroed, because it just brings the whole page "uptodate" with zeroes even if that may not be the correct uptodate data. Also, other parts of the page may already contain dirty data which would get lost by zeroing it out. Thirdly, the writeback of zeroes to the new blocks will also erase existing blocks. All these conditions are pagecache and/or filesystem corruption. The problem comes about because we didn't keep track of which buffers actually are new or old. However it is not enough just to keep only this state, because at the point we start dirtying parts of the page (new blocks, with zeroes), the handling of IO errors becomes impossible without buffers because the page may only be partially uptodate, in which case the page flags allone cannot capture the state of the parts of the page. So allocate all buffers for the page upfront, but leave them unattached so that they don't pick up any other references and can be freed when we're done. If the error path is hit, then zero the new buffers as the regular buffer path does, then attach the buffers to the page so that it can actually be written out correctly and be subject to the normal IO error handling paths. As an upshot, we save 1K of kernel stack on ia64 or powerpc 64K page systems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 01:24:48 -07:00
fs: fix nobh error handling nobh mode error handling is not just pretty slack, it's wrong. One cannot zero out the whole page to ensure new blocks are zeroed, because it just brings the whole page "uptodate" with zeroes even if that may not be the correct uptodate data. Also, other parts of the page may already contain dirty data which would get lost by zeroing it out. Thirdly, the writeback of zeroes to the new blocks will also erase existing blocks. All these conditions are pagecache and/or filesystem corruption. The problem comes about because we didn't keep track of which buffers actually are new or old. However it is not enough just to keep only this state, because at the point we start dirtying parts of the page (new blocks, with zeroes), the handling of IO errors becomes impossible without buffers because the page may only be partially uptodate, in which case the page flags allone cannot capture the state of the parts of the page. So allocate all buffers for the page upfront, but leave them unattached so that they don't pick up any other references and can be freed when we're done. If the error path is hit, then zero the new buffers as the regular buffer path does, then attach the buffers to the page so that it can actually be written out correctly and be subject to the normal IO error handling paths. As an upshot, we save 1K of kernel stack on ia64 or powerpc 64K page systems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 01:24:48 -07:00
fs: fix nobh error handling nobh mode error handling is not just pretty slack, it's wrong. One cannot zero out the whole page to ensure new blocks are zeroed, because it just brings the whole page "uptodate" with zeroes even if that may not be the correct uptodate data. Also, other parts of the page may already contain dirty data which would get lost by zeroing it out. Thirdly, the writeback of zeroes to the new blocks will also erase existing blocks. All these conditions are pagecache and/or filesystem corruption. The problem comes about because we didn't keep track of which buffers actually are new or old. However it is not enough just to keep only this state, because at the point we start dirtying parts of the page (new blocks, with zeroes), the handling of IO errors becomes impossible without buffers because the page may only be partially uptodate, in which case the page flags allone cannot capture the state of the parts of the page. So allocate all buffers for the page upfront, but leave them unattached so that they don't pick up any other references and can be freed when we're done. If the error path is hit, then zero the new buffers as the regular buffer path does, then attach the buffers to the page so that it can actually be written out correctly and be subject to the normal IO error handling paths. As an upshot, we save 1K of kernel stack on ia64 or powerpc 64K page systems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 01:24:48 -07:00
fs: fix nobh error handling nobh mode error handling is not just pretty slack, it's wrong. One cannot zero out the whole page to ensure new blocks are zeroed, because it just brings the whole page "uptodate" with zeroes even if that may not be the correct uptodate data. Also, other parts of the page may already contain dirty data which would get lost by zeroing it out. Thirdly, the writeback of zeroes to the new blocks will also erase existing blocks. All these conditions are pagecache and/or filesystem corruption. The problem comes about because we didn't keep track of which buffers actually are new or old. However it is not enough just to keep only this state, because at the point we start dirtying parts of the page (new blocks, with zeroes), the handling of IO errors becomes impossible without buffers because the page may only be partially uptodate, in which case the page flags allone cannot capture the state of the parts of the page. So allocate all buffers for the page upfront, but leave them unattached so that they don't pick up any other references and can be freed when we're done. If the error path is hit, then zero the new buffers as the regular buffer path does, then attach the buffers to the page so that it can actually be written out correctly and be subject to the normal IO error handling paths. As an upshot, we save 1K of kernel stack on ia64 or powerpc 64K page systems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 01:24:48 -07:00
fs: fix nobh error handling nobh mode error handling is not just pretty slack, it's wrong. One cannot zero out the whole page to ensure new blocks are zeroed, because it just brings the whole page "uptodate" with zeroes even if that may not be the correct uptodate data. Also, other parts of the page may already contain dirty data which would get lost by zeroing it out. Thirdly, the writeback of zeroes to the new blocks will also erase existing blocks. All these conditions are pagecache and/or filesystem corruption. The problem comes about because we didn't keep track of which buffers actually are new or old. However it is not enough just to keep only this state, because at the point we start dirtying parts of the page (new blocks, with zeroes), the handling of IO errors becomes impossible without buffers because the page may only be partially uptodate, in which case the page flags allone cannot capture the state of the parts of the page. So allocate all buffers for the page upfront, but leave them unattached so that they don't pick up any other references and can be freed when we're done. If the error path is hit, then zero the new buffers as the regular buffer path does, then attach the buffers to the page so that it can actually be written out correctly and be subject to the normal IO error handling paths. As an upshot, we save 1K of kernel stack on ia64 or powerpc 64K page systems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 01:24:48 -07:00
fs: fix nobh error handling nobh mode error handling is not just pretty slack, it's wrong. One cannot zero out the whole page to ensure new blocks are zeroed, because it just brings the whole page "uptodate" with zeroes even if that may not be the correct uptodate data. Also, other parts of the page may already contain dirty data which would get lost by zeroing it out. Thirdly, the writeback of zeroes to the new blocks will also erase existing blocks. All these conditions are pagecache and/or filesystem corruption. The problem comes about because we didn't keep track of which buffers actually are new or old. However it is not enough just to keep only this state, because at the point we start dirtying parts of the page (new blocks, with zeroes), the handling of IO errors becomes impossible without buffers because the page may only be partially uptodate, in which case the page flags allone cannot capture the state of the parts of the page. So allocate all buffers for the page upfront, but leave them unattached so that they don't pick up any other references and can be freed when we're done. If the error path is hit, then zero the new buffers as the regular buffer path does, then attach the buffers to the page so that it can actually be written out correctly and be subject to the normal IO error handling paths. As an upshot, we save 1K of kernel stack on ia64 or powerpc 64K page systems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 01:24:48 -07:00
fs: fix nobh error handling nobh mode error handling is not just pretty slack, it's wrong. One cannot zero out the whole page to ensure new blocks are zeroed, because it just brings the whole page "uptodate" with zeroes even if that may not be the correct uptodate data. Also, other parts of the page may already contain dirty data which would get lost by zeroing it out. Thirdly, the writeback of zeroes to the new blocks will also erase existing blocks. All these conditions are pagecache and/or filesystem corruption. The problem comes about because we didn't keep track of which buffers actually are new or old. However it is not enough just to keep only this state, because at the point we start dirtying parts of the page (new blocks, with zeroes), the handling of IO errors becomes impossible without buffers because the page may only be partially uptodate, in which case the page flags allone cannot capture the state of the parts of the page. So allocate all buffers for the page upfront, but leave them unattached so that they don't pick up any other references and can be freed when we're done. If the error path is hit, then zero the new buffers as the regular buffer path does, then attach the buffers to the page so that it can actually be written out correctly and be subject to the normal IO error handling paths. As an upshot, we save 1K of kernel stack on ia64 or powerpc 64K page systems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 01:24:48 -07:00
fs: fix nobh error handling nobh mode error handling is not just pretty slack, it's wrong. One cannot zero out the whole page to ensure new blocks are zeroed, because it just brings the whole page "uptodate" with zeroes even if that may not be the correct uptodate data. Also, other parts of the page may already contain dirty data which would get lost by zeroing it out. Thirdly, the writeback of zeroes to the new blocks will also erase existing blocks. All these conditions are pagecache and/or filesystem corruption. The problem comes about because we didn't keep track of which buffers actually are new or old. However it is not enough just to keep only this state, because at the point we start dirtying parts of the page (new blocks, with zeroes), the handling of IO errors becomes impossible without buffers because the page may only be partially uptodate, in which case the page flags allone cannot capture the state of the parts of the page. So allocate all buffers for the page upfront, but leave them unattached so that they don't pick up any other references and can be freed when we're done. If the error path is hit, then zero the new buffers as the regular buffer path does, then attach the buffers to the page so that it can actually be written out correctly and be subject to the normal IO error handling paths. As an upshot, we save 1K of kernel stack on ia64 or powerpc 64K page systems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 01:24:48 -07:00
fs: fix nobh error handling nobh mode error handling is not just pretty slack, it's wrong. One cannot zero out the whole page to ensure new blocks are zeroed, because it just brings the whole page "uptodate" with zeroes even if that may not be the correct uptodate data. Also, other parts of the page may already contain dirty data which would get lost by zeroing it out. Thirdly, the writeback of zeroes to the new blocks will also erase existing blocks. All these conditions are pagecache and/or filesystem corruption. The problem comes about because we didn't keep track of which buffers actually are new or old. However it is not enough just to keep only this state, because at the point we start dirtying parts of the page (new blocks, with zeroes), the handling of IO errors becomes impossible without buffers because the page may only be partially uptodate, in which case the page flags allone cannot capture the state of the parts of the page. So allocate all buffers for the page upfront, but leave them unattached so that they don't pick up any other references and can be freed when we're done. If the error path is hit, then zero the new buffers as the regular buffer path does, then attach the buffers to the page so that it can actually be written out correctly and be subject to the normal IO error handling paths. As an upshot, we save 1K of kernel stack on ia64 or powerpc 64K page systems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 01:24:48 -07:00
fs: fix nobh error handling nobh mode error handling is not just pretty slack, it's wrong. One cannot zero out the whole page to ensure new blocks are zeroed, because it just brings the whole page "uptodate" with zeroes even if that may not be the correct uptodate data. Also, other parts of the page may already contain dirty data which would get lost by zeroing it out. Thirdly, the writeback of zeroes to the new blocks will also erase existing blocks. All these conditions are pagecache and/or filesystem corruption. The problem comes about because we didn't keep track of which buffers actually are new or old. However it is not enough just to keep only this state, because at the point we start dirtying parts of the page (new blocks, with zeroes), the handling of IO errors becomes impossible without buffers because the page may only be partially uptodate, in which case the page flags allone cannot capture the state of the parts of the page. So allocate all buffers for the page upfront, but leave them unattached so that they don't pick up any other references and can be freed when we're done. If the error path is hit, then zero the new buffers as the regular buffer path does, then attach the buffers to the page so that it can actually be written out correctly and be subject to the normal IO error handling paths. As an upshot, we save 1K of kernel stack on ia64 or powerpc 64K page systems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 01:24:48 -07:00
fs: fix nobh error handling nobh mode error handling is not just pretty slack, it's wrong. One cannot zero out the whole page to ensure new blocks are zeroed, because it just brings the whole page "uptodate" with zeroes even if that may not be the correct uptodate data. Also, other parts of the page may already contain dirty data which would get lost by zeroing it out. Thirdly, the writeback of zeroes to the new blocks will also erase existing blocks. All these conditions are pagecache and/or filesystem corruption. The problem comes about because we didn't keep track of which buffers actually are new or old. However it is not enough just to keep only this state, because at the point we start dirtying parts of the page (new blocks, with zeroes), the handling of IO errors becomes impossible without buffers because the page may only be partially uptodate, in which case the page flags allone cannot capture the state of the parts of the page. So allocate all buffers for the page upfront, but leave them unattached so that they don't pick up any other references and can be freed when we're done. If the error path is hit, then zero the new buffers as the regular buffer path does, then attach the buffers to the page so that it can actually be written out correctly and be subject to the normal IO error handling paths. As an upshot, we save 1K of kernel stack on ia64 or powerpc 64K page systems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 01:24:48 -07:00
fs: fix nobh error handling nobh mode error handling is not just pretty slack, it's wrong. One cannot zero out the whole page to ensure new blocks are zeroed, because it just brings the whole page "uptodate" with zeroes even if that may not be the correct uptodate data. Also, other parts of the page may already contain dirty data which would get lost by zeroing it out. Thirdly, the writeback of zeroes to the new blocks will also erase existing blocks. All these conditions are pagecache and/or filesystem corruption. The problem comes about because we didn't keep track of which buffers actually are new or old. However it is not enough just to keep only this state, because at the point we start dirtying parts of the page (new blocks, with zeroes), the handling of IO errors becomes impossible without buffers because the page may only be partially uptodate, in which case the page flags allone cannot capture the state of the parts of the page. So allocate all buffers for the page upfront, but leave them unattached so that they don't pick up any other references and can be freed when we're done. If the error path is hit, then zero the new buffers as the regular buffer path does, then attach the buffers to the page so that it can actually be written out correctly and be subject to the normal IO error handling paths. As an upshot, we save 1K of kernel stack on ia64 or powerpc 64K page systems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 01:24:48 -07:00
fs: fix nobh error handling nobh mode error handling is not just pretty slack, it's wrong. One cannot zero out the whole page to ensure new blocks are zeroed, because it just brings the whole page "uptodate" with zeroes even if that may not be the correct uptodate data. Also, other parts of the page may already contain dirty data which would get lost by zeroing it out. Thirdly, the writeback of zeroes to the new blocks will also erase existing blocks. All these conditions are pagecache and/or filesystem corruption. The problem comes about because we didn't keep track of which buffers actually are new or old. However it is not enough just to keep only this state, because at the point we start dirtying parts of the page (new blocks, with zeroes), the handling of IO errors becomes impossible without buffers because the page may only be partially uptodate, in which case the page flags allone cannot capture the state of the parts of the page. So allocate all buffers for the page upfront, but leave them unattached so that they don't pick up any other references and can be freed when we're done. If the error path is hit, then zero the new buffers as the regular buffer path does, then attach the buffers to the page so that it can actually be written out correctly and be subject to the normal IO error handling paths. As an upshot, we save 1K of kernel stack on ia64 or powerpc 64K page systems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 01:24:48 -07:00
fs: fix nobh error handling nobh mode error handling is not just pretty slack, it's wrong. One cannot zero out the whole page to ensure new blocks are zeroed, because it just brings the whole page "uptodate" with zeroes even if that may not be the correct uptodate data. Also, other parts of the page may already contain dirty data which would get lost by zeroing it out. Thirdly, the writeback of zeroes to the new blocks will also erase existing blocks. All these conditions are pagecache and/or filesystem corruption. The problem comes about because we didn't keep track of which buffers actually are new or old. However it is not enough just to keep only this state, because at the point we start dirtying parts of the page (new blocks, with zeroes), the handling of IO errors becomes impossible without buffers because the page may only be partially uptodate, in which case the page flags allone cannot capture the state of the parts of the page. So allocate all buffers for the page upfront, but leave them unattached so that they don't pick up any other references and can be freed when we're done. If the error path is hit, then zero the new buffers as the regular buffer path does, then attach the buffers to the page so that it can actually be written out correctly and be subject to the normal IO error handling paths. As an upshot, we save 1K of kernel stack on ia64 or powerpc 64K page systems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 01:24:48 -07:00
fs: fix nobh error handling nobh mode error handling is not just pretty slack, it's wrong. One cannot zero out the whole page to ensure new blocks are zeroed, because it just brings the whole page "uptodate" with zeroes even if that may not be the correct uptodate data. Also, other parts of the page may already contain dirty data which would get lost by zeroing it out. Thirdly, the writeback of zeroes to the new blocks will also erase existing blocks. All these conditions are pagecache and/or filesystem corruption. The problem comes about because we didn't keep track of which buffers actually are new or old. However it is not enough just to keep only this state, because at the point we start dirtying parts of the page (new blocks, with zeroes), the handling of IO errors becomes impossible without buffers because the page may only be partially uptodate, in which case the page flags allone cannot capture the state of the parts of the page. So allocate all buffers for the page upfront, but leave them unattached so that they don't pick up any other references and can be freed when we're done. If the error path is hit, then zero the new buffers as the regular buffer path does, then attach the buffers to the page so that it can actually be written out correctly and be subject to the normal IO error handling paths. As an upshot, we save 1K of kernel stack on ia64 or powerpc 64K page systems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 01:24:48 -07:00
fs: fix nobh error handling nobh mode error handling is not just pretty slack, it's wrong. One cannot zero out the whole page to ensure new blocks are zeroed, because it just brings the whole page "uptodate" with zeroes even if that may not be the correct uptodate data. Also, other parts of the page may already contain dirty data which would get lost by zeroing it out. Thirdly, the writeback of zeroes to the new blocks will also erase existing blocks. All these conditions are pagecache and/or filesystem corruption. The problem comes about because we didn't keep track of which buffers actually are new or old. However it is not enough just to keep only this state, because at the point we start dirtying parts of the page (new blocks, with zeroes), the handling of IO errors becomes impossible without buffers because the page may only be partially uptodate, in which case the page flags allone cannot capture the state of the parts of the page. So allocate all buffers for the page upfront, but leave them unattached so that they don't pick up any other references and can be freed when we're done. If the error path is hit, then zero the new buffers as the regular buffer path does, then attach the buffers to the page so that it can actually be written out correctly and be subject to the normal IO error handling paths. As an upshot, we save 1K of kernel stack on ia64 or powerpc 64K page systems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 01:24:48 -07:00
fs: fix nobh error handling nobh mode error handling is not just pretty slack, it's wrong. One cannot zero out the whole page to ensure new blocks are zeroed, because it just brings the whole page "uptodate" with zeroes even if that may not be the correct uptodate data. Also, other parts of the page may already contain dirty data which would get lost by zeroing it out. Thirdly, the writeback of zeroes to the new blocks will also erase existing blocks. All these conditions are pagecache and/or filesystem corruption. The problem comes about because we didn't keep track of which buffers actually are new or old. However it is not enough just to keep only this state, because at the point we start dirtying parts of the page (new blocks, with zeroes), the handling of IO errors becomes impossible without buffers because the page may only be partially uptodate, in which case the page flags allone cannot capture the state of the parts of the page. So allocate all buffers for the page upfront, but leave them unattached so that they don't pick up any other references and can be freed when we're done. If the error path is hit, then zero the new buffers as the regular buffer path does, then attach the buffers to the page so that it can actually be written out correctly and be subject to the normal IO error handling paths. As an upshot, we save 1K of kernel stack on ia64 or powerpc 64K page systems. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 01:24:48 -07:00
[PATCH] fix possible PAGE_CACHE_SHIFT overflows We've had two instances recently of overflows when doing 64_bit_value = (32_bit_value << PAGE_CACHE_SHIFT) I did a tree-wide grep of `<<.*PAGE_CACHE_SHIFT' and this is the result. - afs_rxfs_fetch_descriptor.offset is of type off_t, which seems broken. - jfs and jffs are limited to 4GB anyway. - reiserfs map_block_for_writepage() takes an unsigned long for the block - it should take sector_t. (It'll fail for huge filesystems with blocksize<PAGE_CACHE_SIZE) - cramfs_read() needs to use sector_t (I think cramsfs is busted on large filesystems anyway) - affs is limited in file size anyway. - I generally didn't fix 32-bit overflows in directory operations. - arm's __flush_dcache_page() is peculiar. What if the page lies beyond 4G? - gss_wrap_req_priv() needs checking (snd_buf->page_base) Cc: Oleg Drokin <green@linuxhacker.ru> Cc: David Howells <dhowells@redhat.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: <reiserfs-dev@namesys.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Anton Altaparmakov <aia21@cantab.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: <linux-fsdevel@vger.kernel.org> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: Neil Brown <neilb@cse.unsw.edu.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 01:03:05 -08:00
[PATCH] fix possible PAGE_CACHE_SHIFT overflows We've had two instances recently of overflows when doing 64_bit_value = (32_bit_value << PAGE_CACHE_SHIFT) I did a tree-wide grep of `<<.*PAGE_CACHE_SHIFT' and this is the result. - afs_rxfs_fetch_descriptor.offset is of type off_t, which seems broken. - jfs and jffs are limited to 4GB anyway. - reiserfs map_block_for_writepage() takes an unsigned long for the block - it should take sector_t. (It'll fail for huge filesystems with blocksize<PAGE_CACHE_SIZE) - cramfs_read() needs to use sector_t (I think cramsfs is busted on large filesystems anyway) - affs is limited in file size anyway. - I generally didn't fix 32-bit overflows in directory operations. - arm's __flush_dcache_page() is peculiar. What if the page lies beyond 4G? - gss_wrap_req_priv() needs checking (snd_buf->page_base) Cc: Oleg Drokin <green@linuxhacker.ru> Cc: David Howells <dhowells@redhat.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: <reiserfs-dev@namesys.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Anton Altaparmakov <aia21@cantab.net> Cc: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Roman Zippel <zippel@linux-m68k.org> Cc: <linux-fsdevel@vger.kernel.org> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: Neil Brown <neilb@cse.unsw.edu.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-08 01:03:05 -08:00