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authorLinus Torvalds <torvalds@linux-foundation.org>2023-06-26 10:01:26 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2023-06-26 10:01:26 -0700
commit2eedfa9e27ed7b22d9c06d8d072ad2dbce4fd635 (patch)
treec7b0bb133f76b23e1d4115478ff4ceb170467ddd /fs/internal.h
parent64bf6ae93e08787f4a6db8dddf671fd3a9c43916 (diff)
parent2454ad83b90afbc6ed2c22ec1310b624c40bf0d3 (diff)
Merge tag 'v6.5/vfs.rename.locking' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs rename locking updates from Christian Brauner: "This contains the work from Jan to fix problems with cross-directory renames originally reported in [1]. To quickly sum it up some filesystems (so far we know at least about ext4, udf, f2fs, ocfs2, likely also reiserfs, gfs2 and others) need to lock the directory when it is being renamed into another directory. This is because we need to update the parent pointer in the directory in that case and if that races with other operations on the directory, in particular a conversion from one directory format into another, bad things can happen. So far we've done the locking in the filesystem code but recently Darrick pointed out in [2] that the RENAME_EXCHANGE case was missing. That one is particularly nasty because RENAME_EXCHANGE can arbitrarily mix regular files and directories and proper lock ordering is not achievable in the filesystems alone. This patch set adds locking into vfs_rename() so that not only parent directories but also moved inodes, regardless of whether they are directories or not, are locked when calling into the filesystem. This means establishing a locking order for unrelated directories. New helpers are added for this purpose and our documentation is updated to cover this in detail. The locking is now actually easier to follow as we now always lock source and target. We've always locked the target independent of whether it was a directory or file and we've always locked source if it was a regular file. The exact details for why this came about can be found in [3] and [4]" Link: https://lore.kernel.org/all/20230117123735.un7wbamlbdihninm@quack3 [1] Link: https://lore.kernel.org/all/20230517045836.GA11594@frogsfrogsfrogs [2] Link: https://lore.kernel.org/all/20230526-schrebergarten-vortag-9cd89694517e@brauner [3] Link: https://lore.kernel.org/all/20230530-seenotrettung-allrad-44f4b00139d4@brauner [4] * tag 'v6.5/vfs.rename.locking' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: fs: Restrict lock_two_nondirectories() to non-directory inodes fs: Lock moved directories fs: Establish locking order for unrelated directories Revert "f2fs: fix potential corruption when moving a directory" Revert "udf: Protect rename against modification of moved directory" ext4: Remove ext4 locking of moved directory
Diffstat (limited to 'fs/internal.h')
-rw-r--r--fs/internal.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/internal.h b/fs/internal.h
index b916b84809f3..5cec33cdf70f 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -193,6 +193,8 @@ extern long prune_icache_sb(struct super_block *sb, struct shrink_control *sc);
int dentry_needs_remove_privs(struct mnt_idmap *, struct dentry *dentry);
bool in_group_or_capable(struct mnt_idmap *idmap,
const struct inode *inode, vfsgid_t vfsgid);
+void lock_two_inodes(struct inode *inode1, struct inode *inode2,
+ unsigned subclass1, unsigned subclass2);
/*
* fs-writeback.c