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ext4: move check under lock scope to close a race.

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fallocate() checks that the file is extent-based and returns
EOPNOTSUPP in case is not. Other tasks can convert from and to
indirect and extent so it's safe to check only after grabbing
the inode mutex.

Signed-off-by: Davide Italiano <dccitaliano@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
This commit is contained in:
Davide Italiano 2015-05-02 23:21:15 -04:00 committed by Theodore Ts'o
parent d2dc317d56
commit 280227a75b
1 changed files with 8 additions and 7 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

15
fs/ext4/extents.c
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@ -4927,13 +4927,6 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
if (ret)
return ret;
/*
* currently supporting (pre)allocate mode for extent-based
* files _only_
*/
if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
return -EOPNOTSUPP;
if (mode & FALLOC_FL_COLLAPSE_RANGE)
return ext4_collapse_range(inode, offset, len);
@ -4955,6 +4948,14 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
mutex_lock(&inode->i_mutex);
/*
* We only support preallocation for extent-based files only
*/
if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
ret = -EOPNOTSUPP;
goto out;
}
if (!(mode & FALLOC_FL_KEEP_SIZE) &&
offset + len > i_size_read(inode)) {
new_size = offset + len;