X-Git-Url: https://git.karo-electronics.de/?a=blobdiff_plain;f=fs%2Ffs-writeback.c;h=9d5360c4c2afbe98d2b46112f131f90d943e00f5;hb=5ebacb271242b3205b865efa1f40a12e981df79d;hp=8e1e5e19d21e1fd60c9f99b3988fee0191c3e901;hpb=b09a75fc5e77b7c58d097236f89b1ff72dcdb562;p=karo-tx-linux.git diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 8e1e5e19d21e..9d5360c4c2af 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -41,8 +41,9 @@ struct wb_writeback_args { long nr_pages; struct super_block *sb; enum writeback_sync_modes sync_mode; - int for_kupdate; - int range_cyclic; + int for_kupdate:1; + int range_cyclic:1; + int for_background:1; }; /* @@ -249,14 +250,25 @@ static void bdi_sync_writeback(struct backing_dev_info *bdi, * completion. Caller need not hold sb s_umount semaphore. * */ -void bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages) +void bdi_start_writeback(struct backing_dev_info *bdi, struct super_block *sb, + long nr_pages) { struct wb_writeback_args args = { + .sb = sb, .sync_mode = WB_SYNC_NONE, .nr_pages = nr_pages, .range_cyclic = 1, }; + /* + * We treat @nr_pages=0 as the special case to do background writeback, + * ie. to sync pages until the background dirty threshold is reached. + */ + if (!nr_pages) { + args.nr_pages = LONG_MAX; + args.for_background = 1; + } + bdi_alloc_queue_work(bdi, &args); } @@ -310,7 +322,7 @@ static bool inode_dirtied_after(struct inode *inode, unsigned long t) * For inodes being constantly redirtied, dirtied_when can get stuck. * It _appears_ to be in the future, but is actually in distant past. * This test is necessary to prevent such wrapped-around relative times - * from permanently stopping the whole pdflush writeback. + * from permanently stopping the whole bdi writeback. */ ret = ret && time_before_eq(inode->dirtied_when, jiffies); #endif @@ -324,13 +336,38 @@ static void move_expired_inodes(struct list_head *delaying_queue, struct list_head *dispatch_queue, unsigned long *older_than_this) { + LIST_HEAD(tmp); + struct list_head *pos, *node; + struct super_block *sb = NULL; + struct inode *inode; + int do_sb_sort = 0; + while (!list_empty(delaying_queue)) { - struct inode *inode = list_entry(delaying_queue->prev, - struct inode, i_list); + inode = list_entry(delaying_queue->prev, struct inode, i_list); if (older_than_this && inode_dirtied_after(inode, *older_than_this)) break; - list_move(&inode->i_list, dispatch_queue); + if (sb && sb != inode->i_sb) + do_sb_sort = 1; + sb = inode->i_sb; + list_move(&inode->i_list, &tmp); + } + + /* just one sb in list, splice to dispatch_queue and we're done */ + if (!do_sb_sort) { + list_splice(&tmp, dispatch_queue); + return; + } + + /* Move inodes from one superblock together */ + while (!list_empty(&tmp)) { + inode = list_entry(tmp.prev, struct inode, i_list); + sb = inode->i_sb; + list_for_each_prev_safe(pos, node, &tmp) { + inode = list_entry(pos, struct inode, i_list); + if (inode->i_sb == sb) + list_move(&inode->i_list, dispatch_queue); + } } } @@ -439,8 +476,18 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc) spin_lock(&inode_lock); inode->i_state &= ~I_SYNC; if (!(inode->i_state & (I_FREEING | I_CLEAR))) { - if (!(inode->i_state & I_DIRTY) && - mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { + if ((inode->i_state & I_DIRTY_PAGES) && wbc->for_kupdate) { + /* + * More pages get dirtied by a fast dirtier. + */ + goto select_queue; + } else if (inode->i_state & I_DIRTY) { + /* + * At least XFS will redirty the inode during the + * writeback (delalloc) and on io completion (isize). + */ + redirty_tail(inode); + } else if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { /* * We didn't write back all the pages. nfs_writepages() * sometimes bales out without doing anything. Redirty @@ -462,6 +509,7 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc) * soon as the queue becomes uncongested. */ inode->i_state |= I_DIRTY_PAGES; +select_queue: if (wbc->nr_to_write <= 0) { /* * slice used up: queue for next turn @@ -484,12 +532,6 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc) inode->i_state |= I_DIRTY_PAGES; redirty_tail(inode); } - } else if (inode->i_state & I_DIRTY) { - /* - * Someone redirtied the inode while were writing back - * the pages. - */ - redirty_tail(inode); } else if (atomic_read(&inode->i_count)) { /* * The inode is clean, inuse @@ -506,6 +548,17 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc) return ret; } +static void unpin_sb_for_writeback(struct super_block **psb) +{ + struct super_block *sb = *psb; + + if (sb) { + up_read(&sb->s_umount); + put_super(sb); + *psb = NULL; + } +} + /* * For WB_SYNC_NONE writeback, the caller does not have the sb pinned * before calling writeback. So make sure that we do pin it, so it doesn't @@ -515,10 +568,19 @@ writeback_single_inode(struct inode *inode, struct writeback_control *wbc) * 1 if we failed. */ static int pin_sb_for_writeback(struct writeback_control *wbc, - struct inode *inode) + struct inode *inode, struct super_block **psb) { struct super_block *sb = inode->i_sb; + /* + * If this sb is already pinned, nothing more to do. If not and + * *psb is non-NULL, unpin the old one first + */ + if (sb == *psb) + return 0; + else if (*psb) + unpin_sb_for_writeback(psb); + /* * Caller must already hold the ref for this */ @@ -532,7 +594,7 @@ static int pin_sb_for_writeback(struct writeback_control *wbc, if (down_read_trylock(&sb->s_umount)) { if (sb->s_root) { spin_unlock(&sb_lock); - return 0; + goto pinned; } /* * umounted, drop rwsem again and fall through to failure @@ -543,24 +605,15 @@ static int pin_sb_for_writeback(struct writeback_control *wbc, sb->s_count--; spin_unlock(&sb_lock); return 1; -} - -static void unpin_sb_for_writeback(struct writeback_control *wbc, - struct inode *inode) -{ - struct super_block *sb = inode->i_sb; - - if (wbc->sync_mode == WB_SYNC_ALL) - return; - - up_read(&sb->s_umount); - put_super(sb); +pinned: + *psb = sb; + return 0; } static void writeback_inodes_wb(struct bdi_writeback *wb, struct writeback_control *wbc) { - struct super_block *sb = wbc->sb; + struct super_block *sb = wbc->sb, *pin_sb = NULL; const int is_blkdev_sb = sb_is_blkdev_sb(sb); const unsigned long start = jiffies; /* livelock avoidance */ @@ -619,7 +672,7 @@ static void writeback_inodes_wb(struct bdi_writeback *wb, if (inode_dirtied_after(inode, start)) break; - if (pin_sb_for_writeback(wbc, inode)) { + if (pin_sb_for_writeback(wbc, inode, &pin_sb)) { requeue_io(inode); continue; } @@ -628,7 +681,6 @@ static void writeback_inodes_wb(struct bdi_writeback *wb, __iget(inode); pages_skipped = wbc->pages_skipped; writeback_single_inode(inode, wbc); - unpin_sb_for_writeback(wbc, inode); if (wbc->pages_skipped != pages_skipped) { /* * writeback is not making progress due to locked @@ -648,6 +700,8 @@ static void writeback_inodes_wb(struct bdi_writeback *wb, wbc->more_io = 1; } + unpin_sb_for_writeback(&pin_sb); + spin_unlock(&inode_lock); /* Leave any unwritten inodes on b_io */ } @@ -706,6 +760,7 @@ static long wb_writeback(struct bdi_writeback *wb, }; unsigned long oldest_jif; long wrote = 0; + struct inode *inode; if (wbc.for_kupdate) { wbc.older_than_this = &oldest_jif; @@ -719,20 +774,16 @@ static long wb_writeback(struct bdi_writeback *wb, for (;;) { /* - * Don't flush anything for non-integrity writeback where - * no nr_pages was given + * Stop writeback when nr_pages has been consumed */ - if (!args->for_kupdate && args->nr_pages <= 0 && - args->sync_mode == WB_SYNC_NONE) + if (args->nr_pages <= 0) break; /* - * If no specific pages were given and this is just a - * periodic background writeout and we are below the - * background dirty threshold, don't do anything + * For background writeout, stop when we are below the + * background dirty threshold */ - if (args->for_kupdate && args->nr_pages <= 0 && - !over_bground_thresh()) + if (args->for_background && !over_bground_thresh()) break; wbc.more_io = 0; @@ -744,13 +795,32 @@ static long wb_writeback(struct bdi_writeback *wb, wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write; /* - * If we ran out of stuff to write, bail unless more_io got set + * If we consumed everything, see if we have more */ - if (wbc.nr_to_write > 0 || wbc.pages_skipped > 0) { - if (wbc.more_io && !wbc.for_kupdate) - continue; + if (wbc.nr_to_write <= 0) + continue; + /* + * Didn't write everything and we don't have more IO, bail + */ + if (!wbc.more_io) break; + /* + * Did we write something? Try for more + */ + if (wbc.nr_to_write < MAX_WRITEBACK_PAGES) + continue; + /* + * Nothing written. Wait for some inode to + * become available for writeback. Otherwise + * we'll just busyloop. + */ + spin_lock(&inode_lock); + if (!list_empty(&wb->b_more_io)) { + inode = list_entry(wb->b_more_io.prev, + struct inode, i_list); + inode_wait_for_writeback(inode); } + spin_unlock(&inode_lock); } return wrote; @@ -1060,9 +1130,6 @@ EXPORT_SYMBOL(__mark_inode_dirty); * If older_than_this is non-NULL, then only write out inodes which * had their first dirtying at a time earlier than *older_than_this. * - * If we're a pdlfush thread, then implement pdflush collision avoidance - * against the entire list. - * * If `bdi' is non-zero then we're being asked to writeback a specific queue. * This function assumes that the blockdev superblock's inodes are backed by * a variety of queues, so all inodes are searched. For other superblocks, @@ -1141,7 +1208,7 @@ void writeback_inodes_sb(struct super_block *sb) nr_to_write = nr_dirty + nr_unstable + (inodes_stat.nr_inodes - inodes_stat.nr_unused); - bdi_writeback_all(sb, nr_to_write); + bdi_start_writeback(sb->s_bdi, sb, nr_to_write); } EXPORT_SYMBOL(writeback_inodes_sb);