diff options
| -rw-r--r-- | fs/fs-writeback.c | 48 | ||||
| -rw-r--r-- | fs/sync.c | 2 | ||||
| -rw-r--r-- | include/linux/backing-dev.h | 2 | ||||
| -rw-r--r-- | include/linux/writeback.h | 10 | ||||
| -rw-r--r-- | mm/page-writeback.c | 4 |
5 files changed, 51 insertions, 15 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 760dc8d..67db897 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -45,6 +45,7 @@ struct wb_writeback_args { int for_kupdate:1; int range_cyclic:1; int for_background:1; + int sb_pinned:1; }; /* @@ -230,6 +231,11 @@ static void bdi_sync_writeback(struct backing_dev_info *bdi, .sync_mode = WB_SYNC_ALL, .nr_pages = LONG_MAX, .range_cyclic = 0, + /* + * Setting sb_pinned is not necessary for WB_SYNC_ALL, but + * lets make it explicitly clear. + */ + .sb_pinned = 1, }; struct bdi_work work; @@ -245,21 +251,23 @@ static void bdi_sync_writeback(struct backing_dev_info *bdi, * @bdi: the backing device to write from * @sb: write inodes from this super_block * @nr_pages: the number of pages to write + * @sb_locked: caller already holds sb umount sem. * * Description: * This does WB_SYNC_NONE opportunistic writeback. The IO is only * started when this function returns, we make no guarentees on - * completion. Caller need not hold sb s_umount semaphore. + * completion. Caller specifies whether sb umount sem is held already or not. * */ void bdi_start_writeback(struct backing_dev_info *bdi, struct super_block *sb, - long nr_pages) + long nr_pages, int sb_locked) { struct wb_writeback_args args = { .sb = sb, .sync_mode = WB_SYNC_NONE, .nr_pages = nr_pages, .range_cyclic = 1, + .sb_pinned = sb_locked, }; /* @@ -577,7 +585,7 @@ static enum sb_pin_state pin_sb_for_writeback(struct writeback_control *wbc, /* * Caller must already hold the ref for this */ - if (wbc->sync_mode == WB_SYNC_ALL) { + if (wbc->sync_mode == WB_SYNC_ALL || wbc->sb_pinned) { WARN_ON(!rwsem_is_locked(&sb->s_umount)); return SB_NOT_PINNED; } @@ -751,6 +759,7 @@ static long wb_writeback(struct bdi_writeback *wb, .for_kupdate = args->for_kupdate, .for_background = args->for_background, .range_cyclic = args->range_cyclic, + .sb_pinned = args->sb_pinned, }; unsigned long oldest_jif; long wrote = 0; @@ -1193,6 +1202,18 @@ static void wait_sb_inodes(struct super_block *sb) iput(old_inode); } +static void __writeback_inodes_sb(struct super_block *sb, int sb_locked) +{ + unsigned long nr_dirty = global_page_state(NR_FILE_DIRTY); + unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS); + long nr_to_write; + + nr_to_write = nr_dirty + nr_unstable + + (inodes_stat.nr_inodes - inodes_stat.nr_unused); + + bdi_start_writeback(sb->s_bdi, sb, nr_to_write, sb_locked); +} + /** * writeback_inodes_sb - writeback dirty inodes from given super_block * @sb: the superblock @@ -1204,18 +1225,23 @@ static void wait_sb_inodes(struct super_block *sb) */ void writeback_inodes_sb(struct super_block *sb) { - unsigned long nr_dirty = global_page_state(NR_FILE_DIRTY); - unsigned long nr_unstable = global_page_state(NR_UNSTABLE_NFS); - long nr_to_write; - - nr_to_write = nr_dirty + nr_unstable + - (inodes_stat.nr_inodes - inodes_stat.nr_unused); - - bdi_start_writeback(sb->s_bdi, sb, nr_to_write); + __writeback_inodes_sb(sb, 0); } EXPORT_SYMBOL(writeback_inodes_sb); /** + * writeback_inodes_sb_locked - writeback dirty inodes from given super_block + * @sb: the superblock + * + * Like writeback_inodes_sb(), except the caller already holds the + * sb umount sem. + */ +void writeback_inodes_sb_locked(struct super_block *sb) +{ + __writeback_inodes_sb(sb, 1); +} + +/** * writeback_inodes_sb_if_idle - start writeback if none underway * @sb: the superblock * @@ -42,7 +42,7 @@ static int __sync_filesystem(struct super_block *sb, int wait) if (wait) sync_inodes_sb(sb); else - writeback_inodes_sb(sb); + writeback_inodes_sb_locked(sb); if (sb->s_op->sync_fs) sb->s_op->sync_fs(sb, wait); diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 7534979..ff8bac6 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -106,7 +106,7 @@ int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev); void bdi_unregister(struct backing_dev_info *bdi); int bdi_setup_and_register(struct backing_dev_info *, char *, unsigned int); void bdi_start_writeback(struct backing_dev_info *bdi, struct super_block *sb, - long nr_pages); + long nr_pages, int sb_locked); int bdi_writeback_task(struct bdi_writeback *wb); int bdi_has_dirty_io(struct backing_dev_info *bdi); diff --git a/include/linux/writeback.h b/include/linux/writeback.h index eb38a2c..47e1c68 100644 --- a/include/linux/writeback.h +++ b/include/linux/writeback.h @@ -65,6 +65,15 @@ struct writeback_control { * so we use a single control to update them */ unsigned no_nrwrite_index_update:1; + + /* + * For WB_SYNC_ALL, the sb must always be pinned. For WB_SYNC_NONE, + * the writeback code will pin the sb for the caller. However, + * for eg umount, the caller does WB_SYNC_NONE but already has + * the sb pinned. If the below is set, caller already has the + * sb pinned. + */ + unsigned sb_pinned:1; }; /* @@ -73,6 +82,7 @@ struct writeback_control { struct bdi_writeback; int inode_wait(void *); void writeback_inodes_sb(struct super_block *); +void writeback_inodes_sb_locked(struct super_block *); int writeback_inodes_sb_if_idle(struct super_block *); void sync_inodes_sb(struct super_block *); void writeback_inodes_wbc(struct writeback_control *wbc); diff --git a/mm/page-writeback.c b/mm/page-writeback.c index d0f2b37..53b2fcf 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -597,7 +597,7 @@ static void balance_dirty_pages(struct address_space *mapping, (!laptop_mode && ((global_page_state(NR_FILE_DIRTY) + global_page_state(NR_UNSTABLE_NFS)) > background_thresh))) - bdi_start_writeback(bdi, NULL, 0); + bdi_start_writeback(bdi, NULL, 0, 0); } void set_page_dirty_balance(struct page *page, int page_mkwrite) @@ -705,7 +705,7 @@ void laptop_mode_timer_fn(unsigned long data) */ if (bdi_has_dirty_io(&q->backing_dev_info)) - bdi_start_writeback(&q->backing_dev_info, NULL, nr_pages); + bdi_start_writeback(&q->backing_dev_info, NULL, 0, nr_pages); } /* |