diff options
| author | Theodore Ts'o <tytso@mit.edu> | 2017-10-06 23:09:55 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-11-30 08:39:04 +0000 |
| commit | 9cdd4bfc42685732ac4d77650a4afac4e743b847 (patch) | |
| tree | 6de3e78c1ad5dc4edcf849b0a87bde9356df36b1 /fs | |
| parent | 2946ebe90ecf7f506e3e1fc49d41406bfaade551 (diff) | |
ext4: fix interaction between i_size, fallocate, and delalloc after a crash
commit 51e3ae81ec58e95f10a98ef3dd6d7bce5d8e35a2 upstream.
If there are pending writes subject to delayed allocation, then i_size
will show size after the writes have completed, while i_disksize
contains the value of i_size on the disk (since the writes have not
been persisted to disk).
If fallocate(2) is called with the FALLOC_FL_KEEP_SIZE flag, either
with or without the FALLOC_FL_ZERO_RANGE flag set, and the new size
after the fallocate(2) is between i_size and i_disksize, then after a
crash, if a journal commit has resulted in the changes made by the
fallocate() call to be persisted after a crash, but the delayed
allocation write has not resolved itself, i_size would not be updated,
and this would cause the following e2fsck complaint:
Inode 12, end of extent exceeds allowed value
(logical block 33, physical block 33441, len 7)
This can only take place on a sparse file, where the fallocate(2) call
is allocating blocks in a range which is before a pending delayed
allocation write which is extending i_size. Since this situation is
quite rare, and the window in which the crash must take place is
typically < 30 seconds, in practice this condition will rarely happen.
Nevertheless, it can be triggered in testing, and in particular by
xfstests generic/456.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reported-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/ext4/extents.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index a3e0b3b7441d..a77cbc5b657b 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -4803,7 +4803,8 @@ static long ext4_zero_range(struct file *file, loff_t offset, } if (!(mode & FALLOC_FL_KEEP_SIZE) && - offset + len > i_size_read(inode)) { + (offset + len > i_size_read(inode) || + offset + len > EXT4_I(inode)->i_disksize)) { new_size = offset + len; ret = inode_newsize_ok(inode, new_size); if (ret) @@ -4974,7 +4975,8 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len) } if (!(mode & FALLOC_FL_KEEP_SIZE) && - offset + len > i_size_read(inode)) { + (offset + len > i_size_read(inode) || + offset + len > EXT4_I(inode)->i_disksize)) { new_size = offset + len; ret = inode_newsize_ok(inode, new_size); if (ret) |