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| author | Eryu Guan | 2018-03-22 16:44:59 +0100 |
|---|---|---|
| committer | Theodore Ts'o | 2018-03-22 16:44:59 +0100 |
| commit | 45d8ec4d9fd5468c08f2ef0b2b132bb62dc81a3d (patch) | |
| tree | 44e883a14a95d665cf1064f16f9cefb2f7f983e6 /fs/ext4/inode.c | |
| parent | ext4: protect i_disksize update by i_data_sem in direct write path (diff) | |
| download | kernel-qcow2-linux-45d8ec4d9fd5468c08f2ef0b2b132bb62dc81a3d.tar.gz kernel-qcow2-linux-45d8ec4d9fd5468c08f2ef0b2b132bb62dc81a3d.tar.xz kernel-qcow2-linux-45d8ec4d9fd5468c08f2ef0b2b132bb62dc81a3d.zip | |
ext4: update i_disksize if direct write past ondisk size
Currently in ext4 direct write path, we update i_disksize only when
new eof is greater than i_size, and don't update it even when new
eof is greater than i_disksize but less than i_size. This doesn't
work well with delalloc buffer write, which updates i_size and
i_disksize only when delalloc blocks are resolved (at writeback
time), the i_disksize from direct write can be lost if a previous
buffer write succeeded at write time but failed at writeback time,
then results in corrupted ondisk inode size.
Consider this case, first buffer write 4k data to a new file at
offset 16k with delayed allocation, then direct write 4k data to the
same file at offset 4k before delalloc blocks are resolved, which
doesn't update i_disksize because it writes within i_size(20k), but
the extent tree metadata has been committed in journal. Then
writeback of the delalloc blocks fails (due to device error etc.),
and i_size/i_disksize from buffer write can't be written to disk
(still zero). A subsequent umount/mount cycle recovers journal and
writes extent tree metadata from direct write to disk, but with
i_disksize being zero.
Fix it by updating i_disksize too in direct write path when new eof
is greater than i_disksize but less than i_size, so i_disksize is
always consistent with direct write.
This fixes occasional i_size corruption in fstests generic/475.
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/inode.c')
| -rw-r--r-- | fs/ext4/inode.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index bff44b4a0783..9acac476c15c 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3658,6 +3658,7 @@ static ssize_t ext4_direct_IO_write(struct kiocb *iocb, struct iov_iter *iter) { struct file *file = iocb->ki_filp; struct inode *inode = file->f_mapping->host; + struct ext4_inode_info *ei = EXT4_I(inode); ssize_t ret; loff_t offset = iocb->ki_pos; size_t count = iov_iter_count(iter); @@ -3668,7 +3669,7 @@ static ssize_t ext4_direct_IO_write(struct kiocb *iocb, struct iov_iter *iter) int orphan = 0; handle_t *handle; - if (final_size > inode->i_size) { + if (final_size > inode->i_size || final_size > ei->i_disksize) { /* Credits for sb + inode write */ handle = ext4_journal_start(inode, EXT4_HT_INODE, 2); if (IS_ERR(handle)) { @@ -3788,9 +3789,10 @@ static ssize_t ext4_direct_IO_write(struct kiocb *iocb, struct iov_iter *iter) ext4_orphan_del(handle, inode); if (ret > 0) { loff_t end = offset + ret; - if (end > inode->i_size) { + if (end > inode->i_size || end > ei->i_disksize) { ext4_update_i_disksize(inode, end); - i_size_write(inode, end); + if (end > inode->i_size) + i_size_write(inode, end); /* * We're going to return a positive `ret' * here due to non-zero-length I/O, so there's |