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Date: Thu, 6 Aug 2015 13:37:41 -0700 From: Kamal Mostafa <kamal@...onical.com> To: linux-kernel@...r.kernel.org, stable@...r.kernel.org, kernel-team@...ts.ubuntu.com Cc: Eryu Guan <guaneryu@...il.com>, Theodore Ts'o <tytso@....edu>, Kamal Mostafa <kamal@...onical.com> Subject: [PATCH 3.13.y-ckt 16/53] ext4: correctly migrate a file with a hole at the beginning 3.13.11-ckt25 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Eryu Guan <guaneryu@...il.com> commit 8974fec7d72e3e02752fe0f27b4c3719c78d9a15 upstream. 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@...il.com> Signed-off-by: Theodore Ts'o <tytso@....edu> Signed-off-by: Kamal Mostafa <kamal@...onical.com> --- fs/ext4/migrate.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c index 05f8414..be92ed2 100644 --- a/fs/ext4/migrate.c +++ b/fs/ext4/migrate.c @@ -616,7 +616,7 @@ 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; @@ -655,11 +655,12 @@ 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; @@ -668,7 +669,7 @@ 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: -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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