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| author | Eryu Guan <guaneryu@gmail.com> | 2015-07-04 00:03:44 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2015-07-04 00:03:44 -0400 |
| commit | 8974fec7d72e3e02752fe0f27b4c3719c78d9a15 (patch) | |
| tree | 0eeac0b96a66c1a21f0e5d7e293238e30a927ea8 | |
| parent | d6f123a9297496ad0b6335fe881504c4b5b2a5e5 (diff) | |
| download | linux-8974fec7d72e3e02752fe0f27b4c3719c78d9a15.tar.bz2 | |
ext4: correctly migrate a file with a hole at the beginning
Currently ext4_ind_migrate() doesn't correctly handle a file which
contains a hole at the beginning of the file. This caused the migration
to be done incorrectly, and then if there is a subsequent following
delayed allocation write to the "hole", this would reclaim the same data
blocks again and results in fs corruption.
# assmuing 4k block size ext4, with delalloc enabled
# skip the first block and write to the second block
xfs_io -fc "pwrite 4k 4k" -c "fsync" /mnt/ext4/testfile
# converting to indirect-mapped file, which would move the data blocks
# to the beginning of the file, but extent status cache still marks
# that region as a hole
chattr -e /mnt/ext4/testfile
# delayed allocation writes to the "hole", reclaim the same data block
# again, results in i_blocks corruption
xfs_io -c "pwrite 0 4k" /mnt/ext4/testfile
umount /mnt/ext4
e2fsck -nf /dev/sda6
...
Inode 53, i_blocks is 16, should be 8. Fix? no
...
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
| -rw-r--r-- | fs/ext4/migrate.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c index 6d8b0c917364..6163ad21cb0e 100644 --- a/fs/ext4/migrate.c +++ b/fs/ext4/migrate.c @@ -620,7 +620,7 @@ int ext4_ind_migrate(struct inode *inode) struct ext4_inode_info *ei = EXT4_I(inode); struct ext4_extent *ex; unsigned int i, len; - ext4_lblk_t end; + ext4_lblk_t start, end; ext4_fsblk_t blk; handle_t *handle; int ret; @@ -659,11 +659,12 @@ int ext4_ind_migrate(struct inode *inode) goto errout; } if (eh->eh_entries == 0) - blk = len = 0; + blk = len = start = end = 0; else { len = le16_to_cpu(ex->ee_len); blk = ext4_ext_pblock(ex); - end = le32_to_cpu(ex->ee_block) + len - 1; + start = le32_to_cpu(ex->ee_block); + end = start + len - 1; if (end >= EXT4_NDIR_BLOCKS) { ret = -EOPNOTSUPP; goto errout; @@ -672,7 +673,7 @@ int ext4_ind_migrate(struct inode *inode) ext4_clear_inode_flag(inode, EXT4_INODE_EXTENTS); memset(ei->i_data, 0, sizeof(ei->i_data)); - for (i=0; i < len; i++) + for (i = start; i <= end; i++) ei->i_data[i] = cpu_to_le32(blk++); ext4_mark_inode_dirty(handle, inode); errout: |