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| author | Theodore Ts'o <tytso@mit.edu> | 2014-04-11 18:35:17 +0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2014-04-11 18:35:17 +0400 |
| commit | 622cad1325e404598fe3b148c3fa640dbaabc235 (patch) | |
| tree | 45f8f60ba6246b9f7276146635c15fb44195f763 /fs/ext4/inode.c | |
| parent | c57ab39b9658315a742b6e61fdc86bb4d20cf566 (diff) | |
| download | linux-622cad1325e404598fe3b148c3fa640dbaabc235.tar.xz | |
ext4: move ext4_update_i_disksize() into mpage_map_and_submit_extent()
The function ext4_update_i_disksize() is used in only one place, in
the function mpage_map_and_submit_extent(). Move its code to simplify
the code paths, and also move the call to ext4_mark_inode_dirty() into
the i_data_sem's critical region, to be consistent with all of the
other places where we update i_disksize. That way, we also keep the
raw_inode's i_disksize protected, to avoid the following race:
CPU #1 CPU #2
down_write(&i_data_sem)
Modify i_disk_size
up_write(&i_data_sem)
down_write(&i_data_sem)
Modify i_disk_size
Copy i_disk_size to on-disk inode
up_write(&i_data_sem)
Copy i_disk_size to on-disk inode
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: stable@vger.kernel.org
Diffstat (limited to 'fs/ext4/inode.c')
| -rw-r--r-- | fs/ext4/inode.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 7b93df9aa182..f023f0cb46fc 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2247,13 +2247,23 @@ static int mpage_map_and_submit_extent(handle_t *handle, return err; } while (map->m_len); - /* Update on-disk size after IO is submitted */ + /* + * Update on-disk size after IO is submitted. Races with + * truncate are avoided by checking i_size under i_data_sem. + */ disksize = ((loff_t)mpd->first_page) << PAGE_CACHE_SHIFT; if (disksize > EXT4_I(inode)->i_disksize) { int err2; - - ext4_wb_update_i_disksize(inode, disksize); + loff_t i_size; + + down_write(&EXT4_I(inode)->i_data_sem); + i_size = i_size_read(inode); + if (disksize > i_size) + disksize = i_size; + if (disksize > EXT4_I(inode)->i_disksize) + EXT4_I(inode)->i_disksize = disksize; err2 = ext4_mark_inode_dirty(handle, inode); + up_write(&EXT4_I(inode)->i_data_sem); if (err2) ext4_error(inode->i_sb, "Failed to mark inode %lu dirty", |