diff options
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/ext4.h | 24 | ||||
| -rw-r--r-- | fs/ext4/inode.c | 17 |
2 files changed, 32 insertions, 9 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 58dede76f75f..3dbc56eb4849 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2432,16 +2432,32 @@ do { \ #define EXT4_FREECLUSTERS_WATERMARK 0 #endif +/* Update i_disksize. Requires i_mutex to avoid races with truncate */ static inline void ext4_update_i_disksize(struct inode *inode, loff_t newsize) { - /* - * XXX: replace with spinlock if seen contended -bzzz - */ + WARN_ON_ONCE(S_ISREG(inode->i_mode) && + !mutex_is_locked(&inode->i_mutex)); + down_write(&EXT4_I(inode)->i_data_sem); + if (newsize > EXT4_I(inode)->i_disksize) + EXT4_I(inode)->i_disksize = 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); - return ; } struct ext4_group_info { diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 38f430119fef..fc4051eb4e0f 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2237,12 +2237,10 @@ static int mpage_map_and_submit_extent(handle_t *handle, /* Update on-disk size after IO is submitted */ disksize = ((loff_t)mpd->first_page) << PAGE_CACHE_SHIFT; - if (disksize > i_size_read(inode)) - disksize = i_size_read(inode); if (disksize > EXT4_I(inode)->i_disksize) { int err2; - ext4_update_i_disksize(inode, disksize); + ext4_wb_update_i_disksize(inode, disksize); err2 = ext4_mark_inode_dirty(handle, inode); if (err2) ext4_error(inode->i_sb, @@ -4627,18 +4625,27 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr) error = ext4_orphan_add(handle, inode); orphan = 1; } + down_write(&EXT4_I(inode)->i_data_sem); EXT4_I(inode)->i_disksize = attr->ia_size; rc = ext4_mark_inode_dirty(handle, inode); if (!error) error = rc; + /* + * We have to update i_size under i_data_sem together + * with i_disksize to avoid races with writeback code + * running ext4_wb_update_i_disksize(). + */ + if (!error) + i_size_write(inode, attr->ia_size); + up_write(&EXT4_I(inode)->i_data_sem); ext4_journal_stop(handle); if (error) { ext4_orphan_del(NULL, inode); goto err_out; } - } + } else + i_size_write(inode, attr->ia_size); - i_size_write(inode, attr->ia_size); /* * Blocks are going to be removed from the inode. Wait * for dio in flight. Temporarily disable |