From 622cad1325e404598fe3b148c3fa640dbaabc235 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Fri, 11 Apr 2014 10:35:17 -0400 Subject: [PATCH] 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" Reviewed-by: Jan Kara Cc: stable@vger.kernel.org --- fs/ext4/ext4.h | 17 ----------------- fs/ext4/inode.c | 14 ++++++++++++-- 2 files changed, 12 insertions(+), 19 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index f1c65dc7cc0a..66946aa62127 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2466,23 +2466,6 @@ static inline void ext4_update_i_disksize(struct inode *inode, loff_t newsize) up_write(&EXT4_I(inode)->i_data_sem); } -/* - * Update i_disksize after writeback has been started. Races with truncate - * are avoided by checking i_size under i_data_sem. - */ -static inline void ext4_wb_update_i_disksize(struct inode *inode, loff_t newsize) -{ - loff_t i_size; - - down_write(&EXT4_I(inode)->i_data_sem); - i_size = i_size_read(inode); - if (newsize > i_size) - newsize = i_size; - if (newsize > EXT4_I(inode)->i_disksize) - EXT4_I(inode)->i_disksize = newsize; - up_write(&EXT4_I(inode)->i_data_sem); -} - struct ext4_group_info { unsigned long bb_state; struct rb_root bb_free_root; 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; + loff_t i_size; - ext4_wb_update_i_disksize(inode, disksize); + 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",