X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=fs%2Ffs-writeback.c;h=300324bd563c924ae87c10db7d5171726f8bffc1;hb=9ef9dc69d4167276c04590d67ee55de8380bc1ad;hp=a4b142a6a2c7f4c870a322bf9d3c9d00be1e8a5f;hpb=5331be090567d9335476f876b2d85427cd7c4426;p=linux-2.6-omap-h63xx.git diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index a4b142a6a2c..300324bd563 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -14,6 +14,7 @@ */ #include +#include #include #include #include @@ -88,7 +89,7 @@ void __mark_inode_dirty(struct inode *inode, int flags) if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) printk(KERN_DEBUG "%s(%d): dirtied inode %lu (%s) on %s\n", - current->comm, current->pid, inode->i_ino, + current->comm, task_pid_nr(current), inode->i_ino, name, inode->i_sb->s_id); } @@ -99,11 +100,11 @@ void __mark_inode_dirty(struct inode *inode, int flags) inode->i_state |= flags; /* - * If the inode is locked, just update its dirty state. + * If the inode is being synced, just update its dirty state. * The unlocker will place the inode on the appropriate * superblock list, based upon its state. */ - if (inode->i_state & I_LOCK) + if (inode->i_state & I_SYNC) goto out; /* @@ -118,7 +119,7 @@ void __mark_inode_dirty(struct inode *inode, int flags) goto out; /* - * If the inode was already on s_dirty or s_io, don't + * If the inode was already on s_dirty/s_io/s_more_io, don't * reposition it (that would break s_dirty time-ordering). */ if (!was_dirty) { @@ -139,6 +140,82 @@ static int write_inode(struct inode *inode, int sync) return 0; } +/* + * Redirty an inode: set its when-it-was dirtied timestamp and move it to the + * furthest end of its superblock's dirty-inode list. + * + * Before stamping the inode's ->dirtied_when, we check to see whether it is + * already the most-recently-dirtied inode on the s_dirty list. If that is + * the case then the inode must have been redirtied while it was being written + * out and we don't reset its dirtied_when. + */ +static void redirty_tail(struct inode *inode) +{ + struct super_block *sb = inode->i_sb; + + if (!list_empty(&sb->s_dirty)) { + struct inode *tail_inode; + + tail_inode = list_entry(sb->s_dirty.next, struct inode, i_list); + if (!time_after_eq(inode->dirtied_when, + tail_inode->dirtied_when)) + inode->dirtied_when = jiffies; + } + list_move(&inode->i_list, &sb->s_dirty); +} + +/* + * requeue inode for re-scanning after sb->s_io list is exhausted. + */ +static void requeue_io(struct inode *inode) +{ + list_move(&inode->i_list, &inode->i_sb->s_more_io); +} + +static void inode_sync_complete(struct inode *inode) +{ + /* + * Prevent speculative execution through spin_unlock(&inode_lock); + */ + smp_mb(); + wake_up_bit(&inode->i_state, __I_SYNC); +} + +/* + * Move expired dirty inodes from @delaying_queue to @dispatch_queue. + */ +static void move_expired_inodes(struct list_head *delaying_queue, + struct list_head *dispatch_queue, + unsigned long *older_than_this) +{ + while (!list_empty(delaying_queue)) { + struct inode *inode = list_entry(delaying_queue->prev, + struct inode, i_list); + if (older_than_this && + time_after(inode->dirtied_when, *older_than_this)) + break; + list_move(&inode->i_list, dispatch_queue); + } +} + +/* + * Queue all expired dirty inodes for io, eldest first. + */ +static void queue_io(struct super_block *sb, + unsigned long *older_than_this) +{ + list_splice_init(&sb->s_more_io, sb->s_io.prev); + move_expired_inodes(&sb->s_dirty, &sb->s_io, older_than_this); +} + +int sb_has_dirty_inodes(struct super_block *sb) +{ + return !list_empty(&sb->s_dirty) || + !list_empty(&sb->s_io) || + !list_empty(&sb->s_more_io); +} +EXPORT_SYMBOL(sb_has_dirty_inodes); + /* * Write a single inode's dirty pages and inode data out to disk. * If `wait' is set, wait on the writeout. @@ -154,15 +231,14 @@ __sync_single_inode(struct inode *inode, struct writeback_control *wbc) { unsigned dirty; struct address_space *mapping = inode->i_mapping; - struct super_block *sb = inode->i_sb; int wait = wbc->sync_mode == WB_SYNC_ALL; int ret; - BUG_ON(inode->i_state & I_LOCK); + BUG_ON(inode->i_state & I_SYNC); - /* Set I_LOCK, reset I_DIRTY */ + /* Set I_SYNC, reset I_DIRTY */ dirty = inode->i_state & I_DIRTY; - inode->i_state |= I_LOCK; + inode->i_state |= I_SYNC; inode->i_state &= ~I_DIRTY; spin_unlock(&inode_lock); @@ -183,24 +259,32 @@ __sync_single_inode(struct inode *inode, struct writeback_control *wbc) } spin_lock(&inode_lock); - inode->i_state &= ~I_LOCK; + inode->i_state &= ~I_SYNC; if (!(inode->i_state & I_FREEING)) { if (!(inode->i_state & I_DIRTY) && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { /* * We didn't write back all the pages. nfs_writepages() * sometimes bales out without doing anything. Redirty - * the inode. It is still on sb->s_io. + * the inode; Move it from s_io onto s_more_io/s_dirty. + */ + /* + * akpm: if the caller was the kupdate function we put + * this inode at the head of s_dirty so it gets first + * consideration. Otherwise, move it to the tail, for + * the reasons described there. I'm not really sure + * how much sense this makes. Presumably I had a good + * reasons for doing it this way, and I'd rather not + * muck with it at present. */ if (wbc->for_kupdate) { /* - * For the kupdate function we leave the inode - * at the head of sb_dirty so it will get more - * writeout as soon as the queue becomes - * uncongested. + * For the kupdate function we move the inode + * to s_more_io so it will get more writeout as + * soon as the queue becomes uncongested. */ inode->i_state |= I_DIRTY_PAGES; - list_move_tail(&inode->i_list, &sb->s_dirty); + requeue_io(inode); } else { /* * Otherwise fully redirty the inode so that @@ -210,15 +294,14 @@ __sync_single_inode(struct inode *inode, struct writeback_control *wbc) * all the other files. */ inode->i_state |= I_DIRTY_PAGES; - inode->dirtied_when = jiffies; - list_move(&inode->i_list, &sb->s_dirty); + redirty_tail(inode); } } else if (inode->i_state & I_DIRTY) { /* * Someone redirtied the inode while were writing back * the pages. */ - list_move(&inode->i_list, &sb->s_dirty); + redirty_tail(inode); } else if (atomic_read(&inode->i_count)) { /* * The inode is clean, inuse @@ -231,7 +314,7 @@ __sync_single_inode(struct inode *inode, struct writeback_control *wbc) list_move(&inode->i_list, &inode_unused); } } - wake_up_inode(inode); + inode_sync_complete(inode); return ret; } @@ -250,11 +333,18 @@ __writeback_single_inode(struct inode *inode, struct writeback_control *wbc) else WARN_ON(inode->i_state & I_WILL_FREE); - if ((wbc->sync_mode != WB_SYNC_ALL) && (inode->i_state & I_LOCK)) { + if ((wbc->sync_mode != WB_SYNC_ALL) && (inode->i_state & I_SYNC)) { struct address_space *mapping = inode->i_mapping; int ret; - list_move(&inode->i_list, &inode->i_sb->s_dirty); + /* + * We're skipping this inode because it's locked, and we're not + * doing writeback-for-data-integrity. Move it to s_more_io so + * that writeback can proceed with the other inodes on s_io. + * We'll have another go at writing back this inode when we + * completed a full scan of s_io. + */ + requeue_io(inode); /* * Even if we don't actually write the inode itself here, @@ -269,16 +359,16 @@ __writeback_single_inode(struct inode *inode, struct writeback_control *wbc) /* * It's a data-integrity sync. We must wait. */ - if (inode->i_state & I_LOCK) { - DEFINE_WAIT_BIT(wq, &inode->i_state, __I_LOCK); + if (inode->i_state & I_SYNC) { + DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC); - wqh = bit_waitqueue(&inode->i_state, __I_LOCK); + wqh = bit_waitqueue(&inode->i_state, __I_SYNC); do { spin_unlock(&inode_lock); __wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE); spin_lock(&inode_lock); - } while (inode->i_state & I_LOCK); + } while (inode->i_state & I_SYNC); } return __sync_single_inode(inode, wbc); } @@ -311,7 +401,7 @@ __writeback_single_inode(struct inode *inode, struct writeback_control *wbc) * The inodes to be written are parked on sb->s_io. They are moved back onto * sb->s_dirty as they are selected for writing. This way, none can be missed * on the writer throttling path, and we get decent balancing between many - * throttled threads: we don't want them all piling up on __wait_on_inode. + * throttled threads: we don't want them all piling up on inode_sync_wait. */ static void sync_sb_inodes(struct super_block *sb, struct writeback_control *wbc) @@ -319,7 +409,7 @@ sync_sb_inodes(struct super_block *sb, struct writeback_control *wbc) const unsigned long start = jiffies; /* livelock avoidance */ if (!wbc->for_kupdate || list_empty(&sb->s_io)) - list_splice_init(&sb->s_dirty, &sb->s_io); + queue_io(sb, wbc->older_than_this); while (!list_empty(&sb->s_io)) { struct inode *inode = list_entry(sb->s_io.prev, @@ -329,7 +419,7 @@ sync_sb_inodes(struct super_block *sb, struct writeback_control *wbc) long pages_skipped; if (!bdi_cap_writeback_dirty(bdi)) { - list_move(&inode->i_list, &sb->s_dirty); + redirty_tail(inode); if (sb_is_blkdev_sb(sb)) { /* * Dirty memory-backed blockdev: the ramdisk @@ -349,14 +439,14 @@ sync_sb_inodes(struct super_block *sb, struct writeback_control *wbc) wbc->encountered_congestion = 1; if (!sb_is_blkdev_sb(sb)) break; /* Skip a congested fs */ - list_move(&inode->i_list, &sb->s_dirty); + requeue_io(inode); continue; /* Skip a congested blockdev */ } if (wbc->bdi && bdi != wbc->bdi) { if (!sb_is_blkdev_sb(sb)) break; /* fs has the wrong queue */ - list_move(&inode->i_list, &sb->s_dirty); + requeue_io(inode); continue; /* blockdev has wrong queue */ } @@ -364,11 +454,6 @@ sync_sb_inodes(struct super_block *sb, struct writeback_control *wbc) if (time_after(inode->dirtied_when, start)) break; - /* Was this inode dirtied too recently? */ - if (wbc->older_than_this && time_after(inode->dirtied_when, - *wbc->older_than_this)) - break; - /* Is another pdflush already flushing this queue? */ if (current_is_pdflush() && !writeback_acquire(bdi)) break; @@ -388,7 +473,7 @@ sync_sb_inodes(struct super_block *sb, struct writeback_control *wbc) * writeback is not making progress due to locked * buffers. Skip this inode for now. */ - list_move(&inode->i_list, &sb->s_dirty); + redirty_tail(inode); } spin_unlock(&inode_lock); iput(inode); @@ -406,7 +491,7 @@ sync_sb_inodes(struct super_block *sb, struct writeback_control *wbc) * Note: * We don't need to grab a reference to superblock here. If it has non-empty * ->s_dirty it's hadn't been killed yet and kill_super() won't proceed - * past sync_inodes_sb() until both the ->s_dirty and ->s_io lists are + * past sync_inodes_sb() until the ->s_dirty/s_io/s_more_io lists are all * empty. Since __sync_single_inode() regains inode_lock before it finally moves * inode from superblock lists we are OK. * @@ -429,7 +514,7 @@ writeback_inodes(struct writeback_control *wbc) restart: sb = sb_entry(super_blocks.prev); for (; sb != sb_entry(&super_blocks); sb = sb_entry(sb->s_list.prev)) { - if (!list_empty(&sb->s_dirty) || !list_empty(&sb->s_io)) { + if (sb_has_dirty_inodes(sb)) { /* we're making our own get_super here */ sb->s_count++; spin_unlock(&sb_lock); @@ -583,7 +668,7 @@ int write_inode_now(struct inode *inode, int sync) ret = __writeback_single_inode(inode, &wbc); spin_unlock(&inode_lock); if (sync) - wait_on_inode(inode); + inode_sync_wait(inode); return ret; } EXPORT_SYMBOL(write_inode_now); @@ -658,7 +743,7 @@ int generic_osync_inode(struct inode *inode, struct address_space *mapping, int err = err2; } else - wait_on_inode(inode); + inode_sync_wait(inode); return err; }