X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=fs%2Ffs-writeback.c;h=9d5360c4c2afbe98d2b46112f131f90d943e00f5;hb=8a1eaa6a5697c4554ecacbd021c668f51318c09e;hp=d6efb36cab2a7d5089e2ec5358424c1990fc3f24;hpb=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2;p=safe%2Fjmp%2Flinux-2.6 diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index d6efb36..9d5360c 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -8,130 +8,377 @@ * pages against inodes. ie: data writeback. Writeout of the * inode itself is not handled here. * - * 10Apr2002 akpm@zip.com.au + * 10Apr2002 Andrew Morton * Split out of fs/inode.c * Additions for address_space-based writeback */ #include +#include #include #include #include #include +#include +#include #include #include #include #include +#include "internal.h" -extern struct super_block *blockdev_superblock; +#define inode_to_bdi(inode) ((inode)->i_mapping->backing_dev_info) + +/* + * We don't actually have pdflush, but this one is exported though /proc... + */ +int nr_pdflush_threads; + +/* + * Passed into wb_writeback(), essentially a subset of writeback_control + */ +struct wb_writeback_args { + long nr_pages; + struct super_block *sb; + enum writeback_sync_modes sync_mode; + int for_kupdate:1; + int range_cyclic:1; + int for_background:1; +}; + +/* + * Work items for the bdi_writeback threads + */ +struct bdi_work { + struct list_head list; /* pending work list */ + struct rcu_head rcu_head; /* for RCU free/clear of work */ + + unsigned long seen; /* threads that have seen this work */ + atomic_t pending; /* number of threads still to do work */ + + struct wb_writeback_args args; /* writeback arguments */ + + unsigned long state; /* flag bits, see WS_* */ +}; + +enum { + WS_USED_B = 0, + WS_ONSTACK_B, +}; + +#define WS_USED (1 << WS_USED_B) +#define WS_ONSTACK (1 << WS_ONSTACK_B) + +static inline bool bdi_work_on_stack(struct bdi_work *work) +{ + return test_bit(WS_ONSTACK_B, &work->state); +} + +static inline void bdi_work_init(struct bdi_work *work, + struct wb_writeback_args *args) +{ + INIT_RCU_HEAD(&work->rcu_head); + work->args = *args; + work->state = WS_USED; +} /** - * __mark_inode_dirty - internal function - * @inode: inode to mark - * @flags: what kind of dirty (i.e. I_DIRTY_SYNC) - * Mark an inode as dirty. Callers should use mark_inode_dirty or - * mark_inode_dirty_sync. - * - * Put the inode on the super block's dirty list. - * - * CAREFUL! We mark it dirty unconditionally, but move it onto the - * dirty list only if it is hashed or if it refers to a blockdev. - * If it was not hashed, it will never be added to the dirty list - * even if it is later hashed, as it will have been marked dirty already. - * - * In short, make sure you hash any inodes _before_ you start marking - * them dirty. - * - * This function *must* be atomic for the I_DIRTY_PAGES case - - * set_page_dirty() is called under spinlock in several places. + * writeback_in_progress - determine whether there is writeback in progress + * @bdi: the device's backing_dev_info structure. * - * Note that for blockdevs, inode->dirtied_when represents the dirtying time of - * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of - * the kernel-internal blockdev inode represents the dirtying time of the - * blockdev's pages. This is why for I_DIRTY_PAGES we always use - * page->mapping->host, so the page-dirtying time is recorded in the internal - * blockdev inode. + * Determine whether there is writeback waiting to be handled against a + * backing device. */ -void __mark_inode_dirty(struct inode *inode, int flags) +int writeback_in_progress(struct backing_dev_info *bdi) { - struct super_block *sb = inode->i_sb; + return !list_empty(&bdi->work_list); +} +static void bdi_work_clear(struct bdi_work *work) +{ + clear_bit(WS_USED_B, &work->state); + smp_mb__after_clear_bit(); /* - * Don't do this for I_DIRTY_PAGES - that doesn't actually - * dirty the inode itself + * work can have disappeared at this point. bit waitq functions + * should be able to tolerate this, provided bdi_sched_wait does + * not dereference it's pointer argument. + */ + wake_up_bit(&work->state, WS_USED_B); +} + +static void bdi_work_free(struct rcu_head *head) +{ + struct bdi_work *work = container_of(head, struct bdi_work, rcu_head); + + if (!bdi_work_on_stack(work)) + kfree(work); + else + bdi_work_clear(work); +} + +static void wb_work_complete(struct bdi_work *work) +{ + const enum writeback_sync_modes sync_mode = work->args.sync_mode; + int onstack = bdi_work_on_stack(work); + + /* + * For allocated work, we can clear the done/seen bit right here. + * For on-stack work, we need to postpone both the clear and free + * to after the RCU grace period, since the stack could be invalidated + * as soon as bdi_work_clear() has done the wakeup. */ - if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { - if (sb->s_op->dirty_inode) - sb->s_op->dirty_inode(inode); + if (!onstack) + bdi_work_clear(work); + if (sync_mode == WB_SYNC_NONE || onstack) + call_rcu(&work->rcu_head, bdi_work_free); +} + +static void wb_clear_pending(struct bdi_writeback *wb, struct bdi_work *work) +{ + /* + * The caller has retrieved the work arguments from this work, + * drop our reference. If this is the last ref, delete and free it + */ + if (atomic_dec_and_test(&work->pending)) { + struct backing_dev_info *bdi = wb->bdi; + + spin_lock(&bdi->wb_lock); + list_del_rcu(&work->list); + spin_unlock(&bdi->wb_lock); + + wb_work_complete(work); } +} + +static void bdi_queue_work(struct backing_dev_info *bdi, struct bdi_work *work) +{ + work->seen = bdi->wb_mask; + BUG_ON(!work->seen); + atomic_set(&work->pending, bdi->wb_cnt); + BUG_ON(!bdi->wb_cnt); /* - * make sure that changes are seen by all cpus before we test i_state - * -- mikulas + * list_add_tail_rcu() contains the necessary barriers to + * make sure the above stores are seen before the item is + * noticed on the list */ - smp_mb(); + spin_lock(&bdi->wb_lock); + list_add_tail_rcu(&work->list, &bdi->work_list); + spin_unlock(&bdi->wb_lock); - /* avoid the locking if we can */ - if ((inode->i_state & flags) == flags) - return; + /* + * If the default thread isn't there, make sure we add it. When + * it gets created and wakes up, we'll run this work. + */ + if (unlikely(list_empty_careful(&bdi->wb_list))) + wake_up_process(default_backing_dev_info.wb.task); + else { + struct bdi_writeback *wb = &bdi->wb; - if (unlikely(block_dump)) { - struct dentry *dentry = NULL; - const char *name = "?"; + if (wb->task) + wake_up_process(wb->task); + } +} - if (!list_empty(&inode->i_dentry)) { - dentry = list_entry(inode->i_dentry.next, - struct dentry, d_alias); - if (dentry && dentry->d_name.name) - name = (const char *) dentry->d_name.name; - } +/* + * Used for on-stack allocated work items. The caller needs to wait until + * the wb threads have acked the work before it's safe to continue. + */ +static void bdi_wait_on_work_clear(struct bdi_work *work) +{ + wait_on_bit(&work->state, WS_USED_B, bdi_sched_wait, + TASK_UNINTERRUPTIBLE); +} + +static void bdi_alloc_queue_work(struct backing_dev_info *bdi, + struct wb_writeback_args *args) +{ + struct bdi_work *work; + + /* + * This is WB_SYNC_NONE writeback, so if allocation fails just + * wakeup the thread for old dirty data writeback + */ + work = kmalloc(sizeof(*work), GFP_ATOMIC); + if (work) { + bdi_work_init(work, args); + bdi_queue_work(bdi, work); + } else { + struct bdi_writeback *wb = &bdi->wb; - 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, - name, inode->i_sb->s_id); + if (wb->task) + wake_up_process(wb->task); } +} - spin_lock(&inode_lock); - if ((inode->i_state & flags) != flags) { - const int was_dirty = inode->i_state & I_DIRTY; +/** + * bdi_sync_writeback - start and wait for writeback + * @bdi: the backing device to write from + * @sb: write inodes from this super_block + * + * Description: + * This does WB_SYNC_ALL data integrity writeback and waits for the + * IO to complete. Callers must hold the sb s_umount semaphore for + * reading, to avoid having the super disappear before we are done. + */ +static void bdi_sync_writeback(struct backing_dev_info *bdi, + struct super_block *sb) +{ + struct wb_writeback_args args = { + .sb = sb, + .sync_mode = WB_SYNC_ALL, + .nr_pages = LONG_MAX, + .range_cyclic = 0, + }; + struct bdi_work work; - inode->i_state |= flags; + bdi_work_init(&work, &args); + work.state |= WS_ONSTACK; - /* - * If the inode is locked, 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) - goto out; + bdi_queue_work(bdi, &work); + bdi_wait_on_work_clear(&work); +} - /* - * Only add valid (hashed) inodes to the superblock's - * dirty list. Add blockdev inodes as well. - */ - if (!S_ISBLK(inode->i_mode)) { - if (hlist_unhashed(&inode->i_hash)) - goto out; - } - if (inode->i_state & (I_FREEING|I_CLEAR)) - goto out; +/** + * bdi_start_writeback - start writeback + * @bdi: the backing device to write from + * @nr_pages: the number of pages to write + * + * 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. + * + */ +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, + }; - /* - * If the inode was already on s_dirty or s_io, don't - * reposition it (that would break s_dirty time-ordering). - */ - if (!was_dirty) { + /* + * 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); +} + +/* + * 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 b_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 bdi_writeback *wb = &inode_to_bdi(inode)->wb; + + if (!list_empty(&wb->b_dirty)) { + struct inode *tail; + + tail = list_entry(wb->b_dirty.next, struct inode, i_list); + if (time_before(inode->dirtied_when, tail->dirtied_when)) inode->dirtied_when = jiffies; - list_move(&inode->i_list, &sb->s_dirty); + } + list_move(&inode->i_list, &wb->b_dirty); +} + +/* + * requeue inode for re-scanning after bdi->b_io list is exhausted. + */ +static void requeue_io(struct inode *inode) +{ + struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; + + list_move(&inode->i_list, &wb->b_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); +} + +static bool inode_dirtied_after(struct inode *inode, unsigned long t) +{ + bool ret = time_after(inode->dirtied_when, t); +#ifndef CONFIG_64BIT + /* + * 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 bdi writeback. + */ + ret = ret && time_before_eq(inode->dirtied_when, jiffies); +#endif + return ret; +} + +/* + * 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) +{ + 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)) { + inode = list_entry(delaying_queue->prev, struct inode, i_list); + if (older_than_this && + inode_dirtied_after(inode, *older_than_this)) + break; + 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); } } -out: - spin_unlock(&inode_lock); } -EXPORT_SYMBOL(__mark_inode_dirty); +/* + * Queue all expired dirty inodes for io, eldest first. + */ +static void queue_io(struct bdi_writeback *wb, unsigned long *older_than_this) +{ + list_splice_init(&wb->b_more_io, wb->b_io.prev); + move_expired_inodes(&wb->b_dirty, &wb->b_io, older_than_this); +} static int write_inode(struct inode *inode, int sync) { @@ -141,7 +388,26 @@ static int write_inode(struct inode *inode, int sync) } /* - * Write a single inode's dirty pages and inode data out to disk. + * Wait for writeback on an inode to complete. + */ +static void inode_wait_for_writeback(struct inode *inode) +{ + DEFINE_WAIT_BIT(wq, &inode->i_state, __I_SYNC); + wait_queue_head_t *wqh; + + 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_SYNC); +} + +/* + * Write out an inode's dirty pages. Called under inode_lock. Either the + * caller has ref on the inode (either via __iget or via syscall against an fd) + * or the inode has I_WILL_FREE set (via generic_forget_inode) + * * If `wait' is set, wait on the writeout. * * The whole writeout design is quite complex and fragile. We want to avoid @@ -151,19 +417,43 @@ static int write_inode(struct inode *inode, int sync) * Called under inode_lock. */ static int -__sync_single_inode(struct inode *inode, struct writeback_control *wbc) +writeback_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; + unsigned dirty; int ret; - BUG_ON(inode->i_state & I_LOCK); + if (!atomic_read(&inode->i_count)) + WARN_ON(!(inode->i_state & (I_WILL_FREE|I_FREEING))); + else + WARN_ON(inode->i_state & I_WILL_FREE); + + if (inode->i_state & I_SYNC) { + /* + * If this inode is locked for writeback and we are not doing + * writeback-for-data-integrity, move it to b_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 b_io. + */ + if (!wait) { + requeue_io(inode); + return 0; + } + + /* + * It's a data-integrity sync. We must wait. + */ + inode_wait_for_writeback(inode); + } + + 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); @@ -184,24 +474,53 @@ __sync_single_inode(struct inode *inode, struct writeback_control *wbc) } spin_lock(&inode_lock); - inode->i_state &= ~I_LOCK; - if (!(inode->i_state & I_FREEING)) { - if (!(inode->i_state & I_DIRTY) && - mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) { + inode->i_state &= ~I_SYNC; + if (!(inode->i_state & (I_FREEING | I_CLEAR))) { + 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 - * the inode. It is still on sb->s_io. + * the inode; Move it from b_io onto b_more_io/b_dirty. + */ + /* + * akpm: if the caller was the kupdate function we put + * this inode at the head of b_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 b_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); +select_queue: + if (wbc->nr_to_write <= 0) { + /* + * slice used up: queue for next turn + */ + requeue_io(inode); + } else { + /* + * somehow blocked: retry later + */ + redirty_tail(inode); + } } else { /* * Otherwise fully redirty the inode so that @@ -211,15 +530,8 @@ __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); } else if (atomic_read(&inode->i_count)) { /* * The inode is clean, inuse @@ -230,98 +542,106 @@ __sync_single_inode(struct inode *inode, struct writeback_control *wbc) * The inode is clean, unused */ list_move(&inode->i_list, &inode_unused); - inodes_stat.nr_unused++; } } - wake_up_inode(inode); + inode_sync_complete(inode); return ret; } -/* - * Write out an inode's dirty pages. Called under inode_lock. - */ -static int -__writeback_single_inode(struct inode *inode, - struct writeback_control *wbc) +static void unpin_sb_for_writeback(struct super_block **psb) { - wait_queue_head_t *wqh; + struct super_block *sb = *psb; - if ((wbc->sync_mode != WB_SYNC_ALL) && (inode->i_state & I_LOCK)) { - list_move(&inode->i_list, &inode->i_sb->s_dirty); - return 0; - } - - /* - * It's a data-integrity sync. We must wait. - */ - if (inode->i_state & I_LOCK) { - DEFINE_WAIT_BIT(wq, &inode->i_state, __I_LOCK); - - wqh = bit_waitqueue(&inode->i_state, __I_LOCK); - do { - __iget(inode); - spin_unlock(&inode_lock); - __wait_on_bit(wqh, &wq, inode_wait, - TASK_UNINTERRUPTIBLE); - iput(inode); - spin_lock(&inode_lock); - } while (inode->i_state & I_LOCK); + if (sb) { + up_read(&sb->s_umount); + put_super(sb); + *psb = NULL; } - return __sync_single_inode(inode, wbc); } /* - * Write out a superblock's list of dirty inodes. A wait will be performed - * upon no inodes, all inodes or the final one, depending upon sync_mode. - * - * 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. - * - * WB_SYNC_HOLD is a hack for sys_sync(): reattach the inode to sb->s_dirty so - * that it can be located for waiting on in __writeback_single_inode(). - * - * Called under inode_lock. - * - * 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, - * assume that all inodes are backed by the same queue. - * - * FIXME: this linear search could get expensive with many fileystems. But - * how to fix? We need to go from an address_space to all inodes which share - * a queue with that address_space. (Easy: have a global "dirty superblocks" - * list). + * 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 + * go away while we are writing inodes from it. * - * 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. + * Returns 0 if the super was successfully pinned (or pinning wasn't needed), + * 1 if we failed. */ -static void -sync_sb_inodes(struct super_block *sb, struct writeback_control *wbc) +static int pin_sb_for_writeback(struct writeback_control *wbc, + struct inode *inode, struct super_block **psb) { - const unsigned long start = jiffies; /* livelock avoidance */ + struct super_block *sb = inode->i_sb; - if (!wbc->for_kupdate || list_empty(&sb->s_io)) - list_splice_init(&sb->s_dirty, &sb->s_io); + /* + * 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); - while (!list_empty(&sb->s_io)) { - struct inode *inode = list_entry(sb->s_io.prev, - struct inode, i_list); - struct address_space *mapping = inode->i_mapping; - struct backing_dev_info *bdi = mapping->backing_dev_info; - long pages_skipped; + /* + * Caller must already hold the ref for this + */ + if (wbc->sync_mode == WB_SYNC_ALL) { + WARN_ON(!rwsem_is_locked(&sb->s_umount)); + return 0; + } - if (!bdi_cap_writeback_dirty(bdi)) { - list_move(&inode->i_list, &sb->s_dirty); - if (sb == blockdev_superblock) { - /* - * Dirty memory-backed blockdev: the ramdisk - * driver does this. Skip just this inode - */ + spin_lock(&sb_lock); + sb->s_count++; + if (down_read_trylock(&sb->s_umount)) { + if (sb->s_root) { + spin_unlock(&sb_lock); + goto pinned; + } + /* + * umounted, drop rwsem again and fall through to failure + */ + up_read(&sb->s_umount); + } + + sb->s_count--; + spin_unlock(&sb_lock); + return 1; +pinned: + *psb = sb; + return 0; +} + +static void writeback_inodes_wb(struct bdi_writeback *wb, + struct writeback_control *wbc) +{ + 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 */ + + spin_lock(&inode_lock); + + if (!wbc->for_kupdate || list_empty(&wb->b_io)) + queue_io(wb, wbc->older_than_this); + + while (!list_empty(&wb->b_io)) { + struct inode *inode = list_entry(wb->b_io.prev, + struct inode, i_list); + long pages_skipped; + + /* + * super block given and doesn't match, skip this inode + */ + if (sb && sb != inode->i_sb) { + redirty_tail(inode); + continue; + } + + if (!bdi_cap_writeback_dirty(wb->bdi)) { + redirty_tail(inode); + if (is_blkdev_sb) { + /* + * Dirty memory-backed blockdev: the ramdisk + * driver does this. Skip just this inode + */ continue; } /* @@ -332,249 +652,609 @@ sync_sb_inodes(struct super_block *sb, struct writeback_control *wbc) break; } - if (wbc->nonblocking && bdi_write_congested(bdi)) { + if (inode->i_state & (I_NEW | I_WILL_FREE)) { + requeue_io(inode); + continue; + } + + if (wbc->nonblocking && bdi_write_congested(wb->bdi)) { wbc->encountered_congestion = 1; - if (sb != blockdev_superblock) + if (!is_blkdev_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 != blockdev_superblock) - break; /* fs has the wrong queue */ - list_move(&inode->i_list, &sb->s_dirty); - continue; /* blockdev has wrong queue */ - } - - /* Was this inode dirtied after sync_sb_inodes was called? */ - 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)) + /* + * Was this inode dirtied after sync_sb_inodes was called? + * This keeps sync from extra jobs and livelock. + */ + if (inode_dirtied_after(inode, start)) break; - /* Is another pdflush already flushing this queue? */ - if (current_is_pdflush() && !writeback_acquire(bdi)) - break; + if (pin_sb_for_writeback(wbc, inode, &pin_sb)) { + requeue_io(inode); + continue; + } - BUG_ON(inode->i_state & I_FREEING); + BUG_ON(inode->i_state & (I_FREEING | I_CLEAR)); __iget(inode); pages_skipped = wbc->pages_skipped; - __writeback_single_inode(inode, wbc); - if (wbc->sync_mode == WB_SYNC_HOLD) { - inode->dirtied_when = jiffies; - list_move(&inode->i_list, &sb->s_dirty); - } - if (current_is_pdflush()) - writeback_release(bdi); + writeback_single_inode(inode, wbc); if (wbc->pages_skipped != pages_skipped) { /* * 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); - cond_resched(); iput(inode); + cond_resched(); spin_lock(&inode_lock); - if (wbc->nr_to_write <= 0) + if (wbc->nr_to_write <= 0) { + wbc->more_io = 1; break; + } + if (!list_empty(&wb->b_more_io)) + wbc->more_io = 1; } - return; /* Leave any unwritten inodes on s_io */ + + unpin_sb_for_writeback(&pin_sb); + + spin_unlock(&inode_lock); + /* Leave any unwritten inodes on b_io */ +} + +void writeback_inodes_wbc(struct writeback_control *wbc) +{ + struct backing_dev_info *bdi = wbc->bdi; + + writeback_inodes_wb(&bdi->wb, wbc); +} + +/* + * The maximum number of pages to writeout in a single bdi flush/kupdate + * operation. We do this so we don't hold I_SYNC against an inode for + * enormous amounts of time, which would block a userspace task which has + * been forced to throttle against that inode. Also, the code reevaluates + * the dirty each time it has written this many pages. + */ +#define MAX_WRITEBACK_PAGES 1024 + +static inline bool over_bground_thresh(void) +{ + unsigned long background_thresh, dirty_thresh; + + get_dirty_limits(&background_thresh, &dirty_thresh, NULL, NULL); + + return (global_page_state(NR_FILE_DIRTY) + + global_page_state(NR_UNSTABLE_NFS) >= background_thresh); } /* - * Start writeback of dirty pagecache data against all unlocked inodes. + * Explicit flushing or periodic writeback of "old" data. * - * 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 - * empty. Since __sync_single_inode() regains inode_lock before it finally moves - * inode from superblock lists we are OK. + * Define "old": the first time one of an inode's pages is dirtied, we mark the + * dirtying-time in the inode's address_space. So this periodic writeback code + * just walks the superblock inode list, writing back any inodes which are + * older than a specific point in time. * - * If `older_than_this' is non-zero then only flush inodes which have a - * flushtime older than *older_than_this. + * Try to run once per dirty_writeback_interval. But if a writeback event + * takes longer than a dirty_writeback_interval interval, then leave a + * one-second gap. * - * If `bdi' is non-zero then we will scan the first inode against each - * superblock until we find the matching ones. One group will be the dirty - * inodes against a filesystem. Then when we hit the dummy blockdev superblock, - * sync_sb_inodes will seekout the blockdev which matches `bdi'. Maybe not - * super-efficient but we're about to do a ton of I/O... + * older_than_this takes precedence over nr_to_write. So we'll only write back + * all dirty pages if they are all attached to "old" mappings. */ -void -writeback_inodes(struct writeback_control *wbc) +static long wb_writeback(struct bdi_writeback *wb, + struct wb_writeback_args *args) { - struct super_block *sb; + struct writeback_control wbc = { + .bdi = wb->bdi, + .sb = args->sb, + .sync_mode = args->sync_mode, + .older_than_this = NULL, + .for_kupdate = args->for_kupdate, + .range_cyclic = args->range_cyclic, + }; + unsigned long oldest_jif; + long wrote = 0; + struct inode *inode; - might_sleep(); - spin_lock(&sb_lock); -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)) { - /* we're making our own get_super here */ - sb->s_count++; - spin_unlock(&sb_lock); - /* - * If we can't get the readlock, there's no sense in - * waiting around, most of the time the FS is going to - * be unmounted by the time it is released. - */ - if (down_read_trylock(&sb->s_umount)) { - if (sb->s_root) { - spin_lock(&inode_lock); - sync_sb_inodes(sb, wbc); - spin_unlock(&inode_lock); - } - up_read(&sb->s_umount); - } - spin_lock(&sb_lock); - if (__put_super_and_need_restart(sb)) - goto restart; - } - if (wbc->nr_to_write <= 0) + if (wbc.for_kupdate) { + wbc.older_than_this = &oldest_jif; + oldest_jif = jiffies - + msecs_to_jiffies(dirty_expire_interval * 10); + } + if (!wbc.range_cyclic) { + wbc.range_start = 0; + wbc.range_end = LLONG_MAX; + } + + for (;;) { + /* + * Stop writeback when nr_pages has been consumed + */ + if (args->nr_pages <= 0) break; + + /* + * For background writeout, stop when we are below the + * background dirty threshold + */ + if (args->for_background && !over_bground_thresh()) + break; + + wbc.more_io = 0; + wbc.encountered_congestion = 0; + wbc.nr_to_write = MAX_WRITEBACK_PAGES; + wbc.pages_skipped = 0; + writeback_inodes_wb(wb, &wbc); + args->nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write; + wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write; + + /* + * If we consumed everything, see if we have more + */ + 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); } - spin_unlock(&sb_lock); + + return wrote; } /* - * writeback and wait upon the filesystem's dirty inodes. The caller will - * do this in two passes - one to write, and one to wait. WB_SYNC_HOLD is - * used to park the written inodes on sb->s_dirty for the wait pass. - * - * A finite limit is set on the number of pages which will be written. - * To prevent infinite livelock of sys_sync(). - * - * We add in the number of potentially dirty inodes, because each inode write - * can dirty pagecache in the underlying blockdev. + * Return the next bdi_work struct that hasn't been processed by this + * wb thread yet. ->seen is initially set for each thread that exists + * for this device, when a thread first notices a piece of work it + * clears its bit. Depending on writeback type, the thread will notify + * completion on either receiving the work (WB_SYNC_NONE) or after + * it is done (WB_SYNC_ALL). */ -void sync_inodes_sb(struct super_block *sb, int wait) +static struct bdi_work *get_next_work_item(struct backing_dev_info *bdi, + struct bdi_writeback *wb) { - struct writeback_control wbc = { - .sync_mode = wait ? WB_SYNC_ALL : WB_SYNC_HOLD, - }; - unsigned long nr_dirty = read_page_state(nr_dirty); - unsigned long nr_unstable = read_page_state(nr_unstable); + struct bdi_work *work, *ret = NULL; - wbc.nr_to_write = nr_dirty + nr_unstable + - (inodes_stat.nr_inodes - inodes_stat.nr_unused) + - nr_dirty + nr_unstable; - wbc.nr_to_write += wbc.nr_to_write / 2; /* Bit more for luck */ - spin_lock(&inode_lock); - sync_sb_inodes(sb, &wbc); - spin_unlock(&inode_lock); + rcu_read_lock(); + + list_for_each_entry_rcu(work, &bdi->work_list, list) { + if (!test_bit(wb->nr, &work->seen)) + continue; + clear_bit(wb->nr, &work->seen); + + ret = work; + break; + } + + rcu_read_unlock(); + return ret; +} + +static long wb_check_old_data_flush(struct bdi_writeback *wb) +{ + unsigned long expired; + long nr_pages; + + expired = wb->last_old_flush + + msecs_to_jiffies(dirty_writeback_interval * 10); + if (time_before(jiffies, expired)) + return 0; + + wb->last_old_flush = jiffies; + nr_pages = global_page_state(NR_FILE_DIRTY) + + global_page_state(NR_UNSTABLE_NFS) + + (inodes_stat.nr_inodes - inodes_stat.nr_unused); + + if (nr_pages) { + struct wb_writeback_args args = { + .nr_pages = nr_pages, + .sync_mode = WB_SYNC_NONE, + .for_kupdate = 1, + .range_cyclic = 1, + }; + + return wb_writeback(wb, &args); + } + + return 0; } /* - * Rather lame livelock avoidance. + * Retrieve work items and do the writeback they describe */ -static void set_sb_syncing(int val) +long wb_do_writeback(struct bdi_writeback *wb, int force_wait) { - struct super_block *sb; - spin_lock(&sb_lock); - sb = sb_entry(super_blocks.prev); - for (; sb != sb_entry(&super_blocks); sb = sb_entry(sb->s_list.prev)) { - sb->s_syncing = val; + struct backing_dev_info *bdi = wb->bdi; + struct bdi_work *work; + long wrote = 0; + + while ((work = get_next_work_item(bdi, wb)) != NULL) { + struct wb_writeback_args args = work->args; + + /* + * Override sync mode, in case we must wait for completion + */ + if (force_wait) + work->args.sync_mode = args.sync_mode = WB_SYNC_ALL; + + /* + * If this isn't a data integrity operation, just notify + * that we have seen this work and we are now starting it. + */ + if (args.sync_mode == WB_SYNC_NONE) + wb_clear_pending(wb, work); + + wrote += wb_writeback(wb, &args); + + /* + * This is a data integrity writeback, so only do the + * notification when we have completed the work. + */ + if (args.sync_mode == WB_SYNC_ALL) + wb_clear_pending(wb, work); } - spin_unlock(&sb_lock); + + /* + * Check for periodic writeback, kupdated() style + */ + wrote += wb_check_old_data_flush(wb); + + return wrote; } /* - * Find a superblock with inodes that need to be synced + * Handle writeback of dirty data for the device backed by this bdi. Also + * wakes up periodically and does kupdated style flushing. */ -static struct super_block *get_super_to_sync(void) +int bdi_writeback_task(struct bdi_writeback *wb) { - struct super_block *sb; -restart: - spin_lock(&sb_lock); - sb = sb_entry(super_blocks.prev); - for (; sb != sb_entry(&super_blocks); sb = sb_entry(sb->s_list.prev)) { - if (sb->s_syncing) + unsigned long last_active = jiffies; + unsigned long wait_jiffies = -1UL; + long pages_written; + + while (!kthread_should_stop()) { + pages_written = wb_do_writeback(wb, 0); + + if (pages_written) + last_active = jiffies; + else if (wait_jiffies != -1UL) { + unsigned long max_idle; + + /* + * Longest period of inactivity that we tolerate. If we + * see dirty data again later, the task will get + * recreated automatically. + */ + max_idle = max(5UL * 60 * HZ, wait_jiffies); + if (time_after(jiffies, max_idle + last_active)) + break; + } + + wait_jiffies = msecs_to_jiffies(dirty_writeback_interval * 10); + schedule_timeout_interruptible(wait_jiffies); + try_to_freeze(); + } + + return 0; +} + +/* + * Schedule writeback for all backing devices. This does WB_SYNC_NONE + * writeback, for integrity writeback see bdi_sync_writeback(). + */ +static void bdi_writeback_all(struct super_block *sb, long nr_pages) +{ + struct wb_writeback_args args = { + .sb = sb, + .nr_pages = nr_pages, + .sync_mode = WB_SYNC_NONE, + }; + struct backing_dev_info *bdi; + + rcu_read_lock(); + + list_for_each_entry_rcu(bdi, &bdi_list, bdi_list) { + if (!bdi_has_dirty_io(bdi)) continue; - sb->s_syncing = 1; - sb->s_count++; - spin_unlock(&sb_lock); - down_read(&sb->s_umount); - if (!sb->s_root) { - drop_super(sb); - goto restart; + + bdi_alloc_queue_work(bdi, &args); + } + + rcu_read_unlock(); +} + +/* + * Start writeback of `nr_pages' pages. If `nr_pages' is zero, write back + * the whole world. + */ +void wakeup_flusher_threads(long nr_pages) +{ + if (nr_pages == 0) + nr_pages = global_page_state(NR_FILE_DIRTY) + + global_page_state(NR_UNSTABLE_NFS); + bdi_writeback_all(NULL, nr_pages); +} + +static noinline void block_dump___mark_inode_dirty(struct inode *inode) +{ + if (inode->i_ino || strcmp(inode->i_sb->s_id, "bdev")) { + struct dentry *dentry; + const char *name = "?"; + + dentry = d_find_alias(inode); + if (dentry) { + spin_lock(&dentry->d_lock); + name = (const char *) dentry->d_name.name; + } + printk(KERN_DEBUG + "%s(%d): dirtied inode %lu (%s) on %s\n", + current->comm, task_pid_nr(current), inode->i_ino, + name, inode->i_sb->s_id); + if (dentry) { + spin_unlock(&dentry->d_lock); + dput(dentry); } - return sb; } - spin_unlock(&sb_lock); - return NULL; } /** - * sync_inodes + * __mark_inode_dirty - internal function + * @inode: inode to mark + * @flags: what kind of dirty (i.e. I_DIRTY_SYNC) + * Mark an inode as dirty. Callers should use mark_inode_dirty or + * mark_inode_dirty_sync. + * + * Put the inode on the super block's dirty list. + * + * CAREFUL! We mark it dirty unconditionally, but move it onto the + * dirty list only if it is hashed or if it refers to a blockdev. + * If it was not hashed, it will never be added to the dirty list + * even if it is later hashed, as it will have been marked dirty already. * - * sync_inodes() goes through each super block's dirty inode list, writes the - * inodes out, waits on the writeout and puts the inodes back on the normal - * list. + * In short, make sure you hash any inodes _before_ you start marking + * them dirty. * - * This is for sys_sync(). fsync_dev() uses the same algorithm. The subtle - * part of the sync functions is that the blockdev "superblock" is processed - * last. This is because the write_inode() function of a typical fs will - * perform no I/O, but will mark buffers in the blockdev mapping as dirty. - * What we want to do is to perform all that dirtying first, and then write - * back all those inode blocks via the blockdev mapping in one sweep. So the - * additional (somewhat redundant) sync_blockdev() calls here are to make - * sure that really happens. Because if we call sync_inodes_sb(wait=1) with - * outstanding dirty inodes, the writeback goes block-at-a-time within the - * filesystem's write_inode(). This is extremely slow. + * This function *must* be atomic for the I_DIRTY_PAGES case - + * set_page_dirty() is called under spinlock in several places. + * + * Note that for blockdevs, inode->dirtied_when represents the dirtying time of + * the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of + * the kernel-internal blockdev inode represents the dirtying time of the + * blockdev's pages. This is why for I_DIRTY_PAGES we always use + * page->mapping->host, so the page-dirtying time is recorded in the internal + * blockdev inode. */ -void sync_inodes(int wait) +void __mark_inode_dirty(struct inode *inode, int flags) { - struct super_block *sb; + struct super_block *sb = inode->i_sb; - set_sb_syncing(0); - while ((sb = get_super_to_sync()) != NULL) { - sync_inodes_sb(sb, 0); - sync_blockdev(sb->s_bdev); - drop_super(sb); + /* + * Don't do this for I_DIRTY_PAGES - that doesn't actually + * dirty the inode itself + */ + if (flags & (I_DIRTY_SYNC | I_DIRTY_DATASYNC)) { + if (sb->s_op->dirty_inode) + sb->s_op->dirty_inode(inode); } - if (wait) { - set_sb_syncing(0); - while ((sb = get_super_to_sync()) != NULL) { - sync_inodes_sb(sb, 1); - sync_blockdev(sb->s_bdev); - drop_super(sb); + + /* + * make sure that changes are seen by all cpus before we test i_state + * -- mikulas + */ + smp_mb(); + + /* avoid the locking if we can */ + if ((inode->i_state & flags) == flags) + return; + + if (unlikely(block_dump)) + block_dump___mark_inode_dirty(inode); + + spin_lock(&inode_lock); + if ((inode->i_state & flags) != flags) { + const int was_dirty = inode->i_state & I_DIRTY; + + inode->i_state |= flags; + + /* + * 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_SYNC) + goto out; + + /* + * Only add valid (hashed) inodes to the superblock's + * dirty list. Add blockdev inodes as well. + */ + if (!S_ISBLK(inode->i_mode)) { + if (hlist_unhashed(&inode->i_hash)) + goto out; } + if (inode->i_state & (I_FREEING|I_CLEAR)) + goto out; + + /* + * If the inode was already on b_dirty/b_io/b_more_io, don't + * reposition it (that would break b_dirty time-ordering). + */ + if (!was_dirty) { + struct bdi_writeback *wb = &inode_to_bdi(inode)->wb; + struct backing_dev_info *bdi = wb->bdi; + + if (bdi_cap_writeback_dirty(bdi) && + !test_bit(BDI_registered, &bdi->state)) { + WARN_ON(1); + printk(KERN_ERR "bdi-%s not registered\n", + bdi->name); + } + + inode->dirtied_when = jiffies; + list_move(&inode->i_list, &wb->b_dirty); + } + } +out: + spin_unlock(&inode_lock); +} +EXPORT_SYMBOL(__mark_inode_dirty); + +/* + * Write out a superblock's list of dirty inodes. A wait will be performed + * upon no inodes, all inodes or the final one, depending upon sync_mode. + * + * 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 `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, + * assume that all inodes are backed by the same queue. + * + * The inodes to be written are parked on bdi->b_io. They are moved back onto + * bdi->b_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 inode_sync_wait. + */ +static void wait_sb_inodes(struct super_block *sb) +{ + struct inode *inode, *old_inode = NULL; + + /* + * We need to be protected against the filesystem going from + * r/o to r/w or vice versa. + */ + WARN_ON(!rwsem_is_locked(&sb->s_umount)); + + spin_lock(&inode_lock); + + /* + * Data integrity sync. Must wait for all pages under writeback, + * because there may have been pages dirtied before our sync + * call, but which had writeout started before we write it out. + * In which case, the inode may not be on the dirty list, but + * we still have to wait for that writeout. + */ + list_for_each_entry(inode, &sb->s_inodes, i_sb_list) { + struct address_space *mapping; + + if (inode->i_state & (I_FREEING|I_CLEAR|I_WILL_FREE|I_NEW)) + continue; + mapping = inode->i_mapping; + if (mapping->nrpages == 0) + continue; + __iget(inode); + spin_unlock(&inode_lock); + /* + * We hold a reference to 'inode' so it couldn't have + * been removed from s_inodes list while we dropped the + * inode_lock. We cannot iput the inode now as we can + * be holding the last reference and we cannot iput it + * under inode_lock. So we keep the reference and iput + * it later. + */ + iput(old_inode); + old_inode = inode; + + filemap_fdatawait(mapping); + + cond_resched(); + + spin_lock(&inode_lock); } + spin_unlock(&inode_lock); + iput(old_inode); +} + +/** + * writeback_inodes_sb - writeback dirty inodes from given super_block + * @sb: the superblock + * + * Start writeback on some inodes on this super_block. No guarantees are made + * on how many (if any) will be written, and this function does not wait + * for IO completion of submitted IO. The number of pages submitted is + * returned. + */ +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); } +EXPORT_SYMBOL(writeback_inodes_sb); /** - * write_inode_now - write an inode to disk - * @inode: inode to write to disk - * @sync: whether the write should be synchronous or not + * sync_inodes_sb - sync sb inode pages + * @sb: the superblock * - * This function commits an inode to disk immediately if it is - * dirty. This is primarily needed by knfsd. + * This function writes and waits on any dirty inode belonging to this + * super_block. The number of pages synced is returned. + */ +void sync_inodes_sb(struct super_block *sb) +{ + bdi_sync_writeback(sb->s_bdi, sb); + wait_sb_inodes(sb); +} +EXPORT_SYMBOL(sync_inodes_sb); + +/** + * write_inode_now - write an inode to disk + * @inode: inode to write to disk + * @sync: whether the write should be synchronous or not + * + * This function commits an inode to disk immediately if it is dirty. This is + * primarily needed by knfsd. + * + * The caller must either have a ref on the inode or must have set I_WILL_FREE. */ - int write_inode_now(struct inode *inode, int sync) { int ret; struct writeback_control wbc = { .nr_to_write = LONG_MAX, - .sync_mode = WB_SYNC_ALL, + .sync_mode = sync ? WB_SYNC_ALL : WB_SYNC_NONE, + .range_start = 0, + .range_end = LLONG_MAX, }; if (!mapping_cap_writeback_dirty(inode->i_mapping)) - return 0; + wbc.nr_to_write = 0; might_sleep(); spin_lock(&inode_lock); - ret = __writeback_single_inode(inode, &wbc); + 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); @@ -595,101 +1275,8 @@ int sync_inode(struct inode *inode, struct writeback_control *wbc) int ret; spin_lock(&inode_lock); - ret = __writeback_single_inode(inode, wbc); + ret = writeback_single_inode(inode, wbc); spin_unlock(&inode_lock); return ret; } EXPORT_SYMBOL(sync_inode); - -/** - * generic_osync_inode - flush all dirty data for a given inode to disk - * @inode: inode to write - * @what: what to write and wait upon - * - * This can be called by file_write functions for files which have the - * O_SYNC flag set, to flush dirty writes to disk. - * - * @what is a bitmask, specifying which part of the inode's data should be - * written and waited upon: - * - * OSYNC_DATA: i_mapping's dirty data - * OSYNC_METADATA: the buffers at i_mapping->private_list - * OSYNC_INODE: the inode itself - */ - -int generic_osync_inode(struct inode *inode, struct address_space *mapping, int what) -{ - int err = 0; - int need_write_inode_now = 0; - int err2; - - current->flags |= PF_SYNCWRITE; - if (what & OSYNC_DATA) - err = filemap_fdatawrite(mapping); - if (what & (OSYNC_METADATA|OSYNC_DATA)) { - err2 = sync_mapping_buffers(mapping); - if (!err) - err = err2; - } - if (what & OSYNC_DATA) { - err2 = filemap_fdatawait(mapping); - if (!err) - err = err2; - } - current->flags &= ~PF_SYNCWRITE; - - spin_lock(&inode_lock); - if ((inode->i_state & I_DIRTY) && - ((what & OSYNC_INODE) || (inode->i_state & I_DIRTY_DATASYNC))) - need_write_inode_now = 1; - spin_unlock(&inode_lock); - - if (need_write_inode_now) { - err2 = write_inode_now(inode, 1); - if (!err) - err = err2; - } - else - wait_on_inode(inode); - - return err; -} - -EXPORT_SYMBOL(generic_osync_inode); - -/** - * writeback_acquire: attempt to get exclusive writeback access to a device - * @bdi: the device's backing_dev_info structure - * - * It is a waste of resources to have more than one pdflush thread blocked on - * a single request queue. Exclusion at the request_queue level is obtained - * via a flag in the request_queue's backing_dev_info.state. - * - * Non-request_queue-backed address_spaces will share default_backing_dev_info, - * unless they implement their own. Which is somewhat inefficient, as this - * may prevent concurrent writeback against multiple devices. - */ -int writeback_acquire(struct backing_dev_info *bdi) -{ - return !test_and_set_bit(BDI_pdflush, &bdi->state); -} - -/** - * writeback_in_progress: determine whether there is writeback in progress - * against a backing device. - * @bdi: the device's backing_dev_info structure. - */ -int writeback_in_progress(struct backing_dev_info *bdi) -{ - return test_bit(BDI_pdflush, &bdi->state); -} - -/** - * writeback_release: relinquish exclusive writeback access against a device. - * @bdi: the device's backing_dev_info structure - */ -void writeback_release(struct backing_dev_info *bdi) -{ - BUG_ON(!writeback_in_progress(bdi)); - clear_bit(BDI_pdflush, &bdi->state); -}