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Amir Goldstein a1a541fbfa ovl: support encoding fid from inode with no alias ... [ Upstream commit c45beebfde ] Dmitry Safonov reported that a WARN_ON() assertion can be trigered by userspace when calling inotify_show_fdinfo() for an overlayfs watched inode, whose dentry aliases were discarded with drop_caches. The WARN_ON() assertion in inotify_show_fdinfo() was removed, because it is possible for encoding file handle to fail for other reason, but the impact of failing to encode an overlayfs file handle goes beyond this assertion. As shown in the LTP test case mentioned in the link below, failure to encode an overlayfs file handle from a non-aliased inode also leads to failure to report an fid with FAN_DELETE_SELF fanotify events. As Dmitry notes in his analyzis of the problem, ovl_encode_fh() fails if it cannot find an alias for the inode, but this failure can be fixed. ovl_encode_fh() seldom uses the alias and in the case of non-decodable file handles, as is often the case with fanotify fid info, ovl_encode_fh() never needs to use the alias to encode a file handle. Defer finding an alias until it is actually needed so ovl_encode_fh() will not fail in the common case of FAN_DELETE_SELF fanotify events. Fixes: 16aac5ad1f ("ovl: support encoding non-decodable file handles") Reported-by: Dmitry Safonov <dima@arista.com> Closes: https://lore.kernel.org/linux-fsdevel/CAOQ4uxiie81voLZZi2zXS1BziXZCM24nXqPAxbu8kxXCUWdwOg@mail.gmail.com/ Signed-off-by: Amir Goldstein <amir73il@gmail.com> Link: https://lore.kernel.org/r/20250105162404.357058-3-amir73il@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>		History 2025-01-17 13:36:10 +01:00
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copy_up.c	ovl: pass realinode to ovl_encode_real_fh() instead of realdentry	2025-01-17 13:36:10 +01:00
dir.c	ovl: remove upper umask handling from ovl_create_upper()	2024-06-12 11:12:24 +02:00
export.c	ovl: support encoding fid from inode with no alias	2025-01-17 13:36:10 +01:00
file.c	ovl: fix file reference leak when submitting aio	2023-10-02 13:08:31 +03:00
inode.c	ovl: properly handle large files in ovl_security_fileattr	2024-12-09 10:33:08 +01:00
Kconfig	ovl: Kconfig: introduce CONFIG_OVERLAY_FS_DEBUG	2023-08-12 19:02:53 +03:00
Makefile	ovl: modify layer parameter parsing	2023-06-20 14:10:40 +03:00
namei.c	ovl: pass realinode to ovl_encode_real_fh() instead of realdentry	2025-01-17 13:36:10 +01:00
overlayfs.h	ovl: pass realinode to ovl_encode_real_fh() instead of realdentry	2025-01-17 13:36:10 +01:00
ovl_entry.h	ovl: make use of ->layers safe in rcu pathwalk	2023-10-02 17:45:02 +03:00
params.c	ovl: fail if trusted xattrs are needed but caller lacks permission	2024-10-10 11:57:44 +02:00
params.h	ovl: store and show the user provided lowerdir mount option	2024-03-26 18:19:18 -04:00
readdir.c	vfs: get rid of old '->iterate' directory operation	2023-08-06 15:08:35 +02:00
super.c	ovl: do not encode lower fh with upper sb_writers held	2025-01-17 13:36:10 +01:00
util.c	ovl: do not encode lower fh with upper sb_writers held	2025-01-17 13:36:10 +01:00