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Btrfs: read inode size after acquiring the mutex when punching a hole

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commit a1a50f60a6 upstream.

In a previous change, commit 12870f1c9b,
I accidentally moved the roundup of inode->i_size to outside of the
critical section delimited by the inode mutex, which is not atomic and
not correct since the size can be changed by other task before we acquire
the mutex. Therefore fix it.

Signed-off-by: Filipe David Borba Manana <fdmanana@gmail.com>
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Filipe Manana
2014-04-26 01:35:31 +01:00
committed by Greg Kroah-Hartman
parent bddf0faccf
commit 2501c4a066
1 changed files with 2 additions and 1 deletions
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3
fs/btrfs/file.c
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@@ -2200,13 +2200,14 @@ static int btrfs_punch_hole(struct inode *inode, loff_t offset, loff_t len)
bool same_page = ((offset >> PAGE_CACHE_SHIFT) ==
((offset + len - 1) >> PAGE_CACHE_SHIFT));
bool no_holes = btrfs_fs_incompat(root->fs_info, NO_HOLES);
u64 ino_size = round_up(inode->i_size, PAGE_CACHE_SIZE);
u64 ino_size;
ret = btrfs_wait_ordered_range(inode, offset, len);
if (ret)
return ret;
mutex_lock(&inode->i_mutex);
ino_size = round_up(inode->i_size, PAGE_CACHE_SIZE);
/*
* We needn't truncate any page which is beyond the end of the file
* because we are sure there is no data there.