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| author | Darrick J. Wong <djwong@kernel.org> | 2022-03-14 20:55:32 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-20 10:34:14 +0300 |
| commit | bb93369f93b568eaa0c2fa56ef1979490372353d (patch) | |
| tree | d7a7eba05cb19888e0429484bf20f109f695fbd8 /fs | |
| parent | 6dded62e5aa6e29f18a1079002109cb6068e9bf6 (diff) | |
| download | linux-bb93369f93b568eaa0c2fa56ef1979490372353d.tar.xz | |
btrfs: fix fallocate to use file_modified to update permissions consistently
[ Upstream commit 05fd9564e9faf0f23b4676385e27d9405cef6637 ]
Since the initial introduction of (posix) fallocate back at the turn of
the century, it has been possible to use this syscall to change the
user-visible contents of files. This can happen by extending the file
size during a preallocation, or through any of the newer modes (punch,
zero range). Because the call can be used to change file contents, we
should treat it like we do any other modification to a file -- update
the mtime, and drop set[ug]id privileges/capabilities.
The VFS function file_modified() does all this for us if pass it a
locked inode, so let's make fallocate drop permissions correctly.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/file.c | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index a1762363f61f..dc1e4d1b7291 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -2878,8 +2878,9 @@ out: return ret; } -static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) +static int btrfs_punch_hole(struct file *file, loff_t offset, loff_t len) { + struct inode *inode = file_inode(file); struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); struct btrfs_root *root = BTRFS_I(inode)->root; struct extent_state *cached_state = NULL; @@ -2911,6 +2912,10 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len) goto out_only_mutex; } + ret = file_modified(file); + if (ret) + goto out_only_mutex; + lockstart = round_up(offset, btrfs_inode_sectorsize(BTRFS_I(inode))); lockend = round_down(offset + len, btrfs_inode_sectorsize(BTRFS_I(inode))) - 1; @@ -3351,7 +3356,7 @@ static long btrfs_fallocate(struct file *file, int mode, return -EOPNOTSUPP; if (mode & FALLOC_FL_PUNCH_HOLE) - return btrfs_punch_hole(inode, offset, len); + return btrfs_punch_hole(file, offset, len); /* * Only trigger disk allocation, don't trigger qgroup reserve @@ -3373,6 +3378,10 @@ static long btrfs_fallocate(struct file *file, int mode, goto out; } + ret = file_modified(file); + if (ret) + goto out; + /* * TODO: Move these two operations after we have checked * accurate reserved space, or fallocate can still fail but |