diff options
Diffstat (limited to 'fs/buffer.c')
| -rw-r--r-- | fs/buffer.c | 2236 |
1 files changed, 1267 insertions, 969 deletions
diff --git a/fs/buffer.c b/fs/buffer.c index b1667986442..eba6e4f621c 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -18,69 +18,103 @@ * async buffer flushing, 1999 Andrea Arcangeli <andrea@suse.de> */ -#include <linux/config.h> #include <linux/kernel.h> #include <linux/syscalls.h> #include <linux/fs.h> #include <linux/mm.h> #include <linux/percpu.h> #include <linux/slab.h> -#include <linux/smp_lock.h> +#include <linux/capability.h> #include <linux/blkdev.h> #include <linux/file.h> #include <linux/quotaops.h> #include <linux/highmem.h> -#include <linux/module.h> +#include <linux/export.h> #include <linux/writeback.h> #include <linux/hash.h> #include <linux/suspend.h> #include <linux/buffer_head.h> +#include <linux/task_io_accounting_ops.h> #include <linux/bio.h> #include <linux/notifier.h> #include <linux/cpu.h> #include <linux/bitops.h> #include <linux/mpage.h> #include <linux/bit_spinlock.h> +#include <trace/events/block.h> static int fsync_buffers_list(spinlock_t *lock, struct list_head *list); -static void invalidate_bh_lrus(void); #define BH_ENTRY(list) list_entry((list), struct buffer_head, b_assoc_buffers) -inline void -init_buffer(struct buffer_head *bh, bh_end_io_t *handler, void *private) +void init_buffer(struct buffer_head *bh, bh_end_io_t *handler, void *private) { bh->b_end_io = handler; bh->b_private = private; } +EXPORT_SYMBOL(init_buffer); -static int sync_buffer(void *word) +inline void touch_buffer(struct buffer_head *bh) { - struct block_device *bd; - struct buffer_head *bh - = container_of(word, struct buffer_head, b_state); + trace_block_touch_buffer(bh); + mark_page_accessed(bh->b_page); +} +EXPORT_SYMBOL(touch_buffer); - smp_mb(); - bd = bh->b_bdev; - if (bd) - blk_run_address_space(bd->bd_inode->i_mapping); +static int sleep_on_buffer(void *word) +{ io_schedule(); return 0; } -void fastcall __lock_buffer(struct buffer_head *bh) +void __lock_buffer(struct buffer_head *bh) { - wait_on_bit_lock(&bh->b_state, BH_Lock, sync_buffer, + wait_on_bit_lock(&bh->b_state, BH_Lock, sleep_on_buffer, TASK_UNINTERRUPTIBLE); } EXPORT_SYMBOL(__lock_buffer); -void fastcall unlock_buffer(struct buffer_head *bh) +void unlock_buffer(struct buffer_head *bh) { - clear_buffer_locked(bh); - smp_mb__after_clear_bit(); + clear_bit_unlock(BH_Lock, &bh->b_state); + smp_mb__after_atomic(); wake_up_bit(&bh->b_state, BH_Lock); } +EXPORT_SYMBOL(unlock_buffer); + +/* + * Returns if the page has dirty or writeback buffers. If all the buffers + * are unlocked and clean then the PageDirty information is stale. If + * any of the pages are locked, it is assumed they are locked for IO. + */ +void buffer_check_dirty_writeback(struct page *page, + bool *dirty, bool *writeback) +{ + struct buffer_head *head, *bh; + *dirty = false; + *writeback = false; + + BUG_ON(!PageLocked(page)); + + if (!page_has_buffers(page)) + return; + + if (PageWriteback(page)) + *writeback = true; + + head = page_buffers(page); + bh = head; + do { + if (buffer_locked(bh)) + *writeback = true; + + if (buffer_dirty(bh)) + *dirty = true; + + bh = bh->b_this_page; + } while (bh != head); +} +EXPORT_SYMBOL(buffer_check_dirty_writeback); /* * Block until a buffer comes unlocked. This doesn't stop it @@ -89,31 +123,44 @@ void fastcall unlock_buffer(struct buffer_head *bh) */ void __wait_on_buffer(struct buffer_head * bh) { - wait_on_bit(&bh->b_state, BH_Lock, sync_buffer, TASK_UNINTERRUPTIBLE); + wait_on_bit(&bh->b_state, BH_Lock, sleep_on_buffer, TASK_UNINTERRUPTIBLE); } +EXPORT_SYMBOL(__wait_on_buffer); static void __clear_page_buffers(struct page *page) { ClearPagePrivate(page); - page->private = 0; + set_page_private(page, 0); page_cache_release(page); } + +static int quiet_error(struct buffer_head *bh) +{ + if (!test_bit(BH_Quiet, &bh->b_state) && printk_ratelimit()) + return 0; + return 1; +} + + static void buffer_io_error(struct buffer_head *bh) { char b[BDEVNAME_SIZE]; - printk(KERN_ERR "Buffer I/O error on device %s, logical block %Lu\n", bdevname(bh->b_bdev, b), (unsigned long long)bh->b_blocknr); } /* - * Default synchronous end-of-IO handler.. Just mark it up-to-date and - * unlock the buffer. This is what ll_rw_block uses too. + * End-of-IO handler helper function which does not touch the bh after + * unlocking it. + * Note: unlock_buffer() sort-of does touch the bh after unlocking it, but + * a race there is benign: unlock_buffer() only use the bh's address for + * hashing after unlocking the buffer, so it doesn't actually touch the bh + * itself. */ -void end_buffer_read_sync(struct buffer_head *bh, int uptodate) +static void __end_buffer_read_notouch(struct buffer_head *bh, int uptodate) { if (uptodate) { set_buffer_uptodate(bh); @@ -122,8 +169,18 @@ void end_buffer_read_sync(struct buffer_head *bh, int uptodate) clear_buffer_uptodate(bh); } unlock_buffer(bh); +} + +/* + * Default synchronous end-of-IO handler.. Just mark it up-to-date and + * unlock the buffer. This is what ll_rw_block uses too. + */ +void end_buffer_read_sync(struct buffer_head *bh, int uptodate) +{ + __end_buffer_read_notouch(bh, uptodate); put_bh(bh); } +EXPORT_SYMBOL(end_buffer_read_sync); void end_buffer_write_sync(struct buffer_head *bh, int uptodate) { @@ -132,7 +189,7 @@ void end_buffer_write_sync(struct buffer_head *bh, int uptodate) if (uptodate) { set_buffer_uptodate(bh); } else { - if (!buffer_eopnotsupp(bh) && printk_ratelimit()) { + if (!quiet_error(bh)) { buffer_io_error(bh); printk(KERN_WARNING "lost page write due to " "I/O error on %s\n", @@ -144,245 +201,7 @@ void end_buffer_write_sync(struct buffer_head *bh, int uptodate) unlock_buffer(bh); put_bh(bh); } - -/* - * Write out and wait upon all the dirty data associated with a block - * device via its mapping. Does not take the superblock lock. - */ -int sync_blockdev(struct block_device *bdev) -{ - int ret = 0; - - if (bdev) { - int err; - - ret = filemap_fdatawrite(bdev->bd_inode->i_mapping); - err = filemap_fdatawait(bdev->bd_inode->i_mapping); - if (!ret) - ret = err; - } - return ret; -} -EXPORT_SYMBOL(sync_blockdev); - -/* - * Write out and wait upon all dirty data associated with this - * superblock. Filesystem data as well as the underlying block - * device. Takes the superblock lock. - */ -int fsync_super(struct super_block *sb) -{ - sync_inodes_sb(sb, 0); - DQUOT_SYNC(sb); - lock_super(sb); - if (sb->s_dirt && sb->s_op->write_super) - sb->s_op->write_super(sb); - unlock_super(sb); - if (sb->s_op->sync_fs) - sb->s_op->sync_fs(sb, 1); - sync_blockdev(sb->s_bdev); - sync_inodes_sb(sb, 1); - - return sync_blockdev(sb->s_bdev); -} - -/* - * Write out and wait upon all dirty data associated with this - * device. Filesystem data as well as the underlying block - * device. Takes the superblock lock. - */ -int fsync_bdev(struct block_device *bdev) -{ - struct super_block *sb = get_super(bdev); - if (sb) { - int res = fsync_super(sb); - drop_super(sb); - return res; - } - return sync_blockdev(bdev); -} - -/** - * freeze_bdev -- lock a filesystem and force it into a consistent state - * @bdev: blockdevice to lock - * - * This takes the block device bd_mount_sem to make sure no new mounts - * happen on bdev until thaw_bdev() is called. - * If a superblock is found on this device, we take the s_umount semaphore - * on it to make sure nobody unmounts until the snapshot creation is done. - */ -struct super_block *freeze_bdev(struct block_device *bdev) -{ - struct super_block *sb; - - down(&bdev->bd_mount_sem); - sb = get_super(bdev); - if (sb && !(sb->s_flags & MS_RDONLY)) { - sb->s_frozen = SB_FREEZE_WRITE; - smp_wmb(); - - sync_inodes_sb(sb, 0); - DQUOT_SYNC(sb); - - lock_super(sb); - if (sb->s_dirt && sb->s_op->write_super) - sb->s_op->write_super(sb); - unlock_super(sb); - - if (sb->s_op->sync_fs) - sb->s_op->sync_fs(sb, 1); - - sync_blockdev(sb->s_bdev); - sync_inodes_sb(sb, 1); - - sb->s_frozen = SB_FREEZE_TRANS; - smp_wmb(); - - sync_blockdev(sb->s_bdev); - - if (sb->s_op->write_super_lockfs) - sb->s_op->write_super_lockfs(sb); - } - - sync_blockdev(bdev); - return sb; /* thaw_bdev releases s->s_umount and bd_mount_sem */ -} -EXPORT_SYMBOL(freeze_bdev); - -/** - * thaw_bdev -- unlock filesystem - * @bdev: blockdevice to unlock - * @sb: associated superblock - * - * Unlocks the filesystem and marks it writeable again after freeze_bdev(). - */ -void thaw_bdev(struct block_device *bdev, struct super_block *sb) -{ - if (sb) { - BUG_ON(sb->s_bdev != bdev); - - if (sb->s_op->unlockfs) - sb->s_op->unlockfs(sb); - sb->s_frozen = SB_UNFROZEN; - smp_wmb(); - wake_up(&sb->s_wait_unfrozen); - drop_super(sb); - } - - up(&bdev->bd_mount_sem); -} -EXPORT_SYMBOL(thaw_bdev); - -/* - * sync everything. Start out by waking pdflush, because that writes back - * all queues in parallel. - */ -static void do_sync(unsigned long wait) -{ - wakeup_pdflush(0); - sync_inodes(0); /* All mappings, inodes and their blockdevs */ - DQUOT_SYNC(NULL); - sync_supers(); /* Write the superblocks */ - sync_filesystems(0); /* Start syncing the filesystems */ - sync_filesystems(wait); /* Waitingly sync the filesystems */ - sync_inodes(wait); /* Mappings, inodes and blockdevs, again. */ - if (!wait) - printk("Emergency Sync complete\n"); - if (unlikely(laptop_mode)) - laptop_sync_completion(); -} - -asmlinkage long sys_sync(void) -{ - do_sync(1); - return 0; -} - -void emergency_sync(void) -{ - pdflush_operation(do_sync, 0); -} - -/* - * Generic function to fsync a file. - * - * filp may be NULL if called via the msync of a vma. - */ - -int file_fsync(struct file *filp, struct dentry *dentry, int datasync) -{ - struct inode * inode = dentry->d_inode; - struct super_block * sb; - int ret, err; - - /* sync the inode to buffers */ - ret = write_inode_now(inode, 0); - - /* sync the superblock to buffers */ - sb = inode->i_sb; - lock_super(sb); - if (sb->s_op->write_super) - sb->s_op->write_super(sb); - unlock_super(sb); - - /* .. finally sync the buffers to disk */ - err = sync_blockdev(sb->s_bdev); - if (!ret) - ret = err; - return ret; -} - -static long do_fsync(unsigned int fd, int datasync) -{ - struct file * file; - struct address_space *mapping; - int ret, err; - - ret = -EBADF; - file = fget(fd); - if (!file) - goto out; - - ret = -EINVAL; - if (!file->f_op || !file->f_op->fsync) { - /* Why? We can still call filemap_fdatawrite */ - goto out_putf; - } - - mapping = file->f_mapping; - - current->flags |= PF_SYNCWRITE; - ret = filemap_fdatawrite(mapping); - - /* - * We need to protect against concurrent writers, - * which could cause livelocks in fsync_buffers_list - */ - down(&mapping->host->i_sem); - err = file->f_op->fsync(file, file->f_dentry, datasync); - if (!ret) - ret = err; - up(&mapping->host->i_sem); - err = filemap_fdatawait(mapping); - if (!ret) - ret = err; - current->flags &= ~PF_SYNCWRITE; - -out_putf: - fput(file); -out: - return ret; -} - -asmlinkage long sys_fsync(unsigned int fd) -{ - return do_fsync(fd, 0); -} - -asmlinkage long sys_fdatasync(unsigned int fd) -{ - return do_fsync(fd, 1); -} +EXPORT_SYMBOL(end_buffer_write_sync); /* * Various filesystems appear to want __find_get_block to be non-blocking. @@ -396,7 +215,7 @@ asmlinkage long sys_fdatasync(unsigned int fd) * private_lock is contended then so is mapping->tree_lock). */ static struct buffer_head * -__find_get_block_slow(struct block_device *bdev, sector_t block, int unused) +__find_get_block_slow(struct block_device *bdev, sector_t block) { struct inode *bd_inode = bdev->bd_inode; struct address_space *bd_mapping = bd_inode->i_mapping; @@ -408,7 +227,7 @@ __find_get_block_slow(struct block_device *bdev, sector_t block, int unused) int all_mapped = 1; index = block >> (PAGE_CACHE_SHIFT - bd_inode->i_blkbits); - page = find_get_page(bd_mapping, index); + page = find_get_page_flags(bd_mapping, index, FGP_ACCESSED); if (!page) goto out; @@ -418,13 +237,13 @@ __find_get_block_slow(struct block_device *bdev, sector_t block, int unused) head = page_buffers(page); bh = head; do { - if (bh->b_blocknr == block) { + if (!buffer_mapped(bh)) + all_mapped = 0; + else if (bh->b_blocknr == block) { ret = bh; get_bh(bh); goto out_unlock; } - if (!buffer_mapped(bh)) - all_mapped = 0; bh = bh->b_this_page; } while (bh != head); @@ -434,11 +253,16 @@ __find_get_block_slow(struct block_device *bdev, sector_t block, int unused) * elsewhere, don't buffer_error if we had some unmapped buffers */ if (all_mapped) { + char b[BDEVNAME_SIZE]; + printk("__find_get_block_slow() failed. " "block=%llu, b_blocknr=%llu\n", - (unsigned long long)block, (unsigned long long)bh->b_blocknr); - printk("b_state=0x%08lx, b_size=%u\n", bh->b_state, bh->b_size); - printk("device blocksize: %d\n", 1 << bd_inode->i_blkbits); + (unsigned long long)block, + (unsigned long long)bh->b_blocknr); + printk("b_state=0x%08lx, b_size=%zu\n", + bh->b_state, bh->b_size); + printk("device %s blocksize: %d\n", bdevname(bdev, b), + 1 << bd_inode->i_blkbits); } out_unlock: spin_unlock(&bd_mapping->private_lock); @@ -447,64 +271,24 @@ out: return ret; } -/* If invalidate_buffers() will trash dirty buffers, it means some kind - of fs corruption is going on. Trashing dirty data always imply losing - information that was supposed to be just stored on the physical layer - by the user. - - Thus invalidate_buffers in general usage is not allwowed to trash - dirty buffers. For example ioctl(FLSBLKBUF) expects dirty data to - be preserved. These buffers are simply skipped. - - We also skip buffers which are still in use. For example this can - happen if a userspace program is reading the block device. - - NOTE: In the case where the user removed a removable-media-disk even if - there's still dirty data not synced on disk (due a bug in the device driver - or due an error of the user), by not destroying the dirty buffers we could - generate corruption also on the next media inserted, thus a parameter is - necessary to handle this case in the most safe way possible (trying - to not corrupt also the new disk inserted with the data belonging to - the old now corrupted disk). Also for the ramdisk the natural thing - to do in order to release the ramdisk memory is to destroy dirty buffers. - - These are two special cases. Normal usage imply the device driver - to issue a sync on the device (without waiting I/O completion) and - then an invalidate_buffers call that doesn't trash dirty buffers. - - For handling cache coherency with the blkdev pagecache the 'update' case - is been introduced. It is needed to re-read from disk any pinned - buffer. NOTE: re-reading from disk is destructive so we can do it only - when we assume nobody is changing the buffercache under our I/O and when - we think the disk contains more recent information than the buffercache. - The update == 1 pass marks the buffers we need to update, the update == 2 - pass does the actual I/O. */ -void invalidate_bdev(struct block_device *bdev, int destroy_dirty_buffers) -{ - invalidate_bh_lrus(); - /* - * FIXME: what about destroy_dirty_buffers? - * We really want to use invalidate_inode_pages2() for - * that, but not until that's cleaned up. - */ - invalidate_inode_pages(bdev->bd_inode->i_mapping); -} - /* - * Kick pdflush then try to free up some ZONE_NORMAL memory. + * Kick the writeback threads then try to free up some ZONE_NORMAL memory. */ static void free_more_memory(void) { - struct zone **zones; - pg_data_t *pgdat; + struct zone *zone; + int nid; - wakeup_pdflush(1024); + wakeup_flusher_threads(1024, WB_REASON_FREE_MORE_MEM); yield(); - for_each_pgdat(pgdat) { - zones = pgdat->node_zonelists[gfp_zone(GFP_NOFS)].zones; - if (*zones) - try_to_free_pages(zones, GFP_NOFS); + for_each_online_node(nid) { + (void)first_zones_zonelist(node_zonelist(nid, GFP_NOFS), + gfp_zone(GFP_NOFS), NULL, + &zone); + if (zone) + try_to_free_pages(node_zonelist(nid, GFP_NOFS), 0, + GFP_NOFS, NULL); } } @@ -527,7 +311,7 @@ static void end_buffer_async_read(struct buffer_head *bh, int uptodate) set_buffer_uptodate(bh); } else { clear_buffer_uptodate(bh); - if (printk_ratelimit()) + if (!quiet_error(bh)) buffer_io_error(bh); SetPageError(page); } @@ -588,13 +372,14 @@ void end_buffer_async_write(struct buffer_head *bh, int uptodate) if (uptodate) { set_buffer_uptodate(bh); } else { - if (printk_ratelimit()) { + if (!quiet_error(bh)) { buffer_io_error(bh); printk(KERN_WARNING "lost page write due to " "I/O error on %s\n", bdevname(bh->b_bdev, b)); } set_bit(AS_EIO, &page->mapping->flags); + set_buffer_write_io_error(bh); clear_buffer_uptodate(bh); SetPageError(page); } @@ -623,6 +408,7 @@ still_busy: local_irq_restore(flags); return; } +EXPORT_SYMBOL(end_buffer_async_write); /* * If a page's buffers are under async readin (end_buffer_async_read @@ -651,11 +437,17 @@ static void mark_buffer_async_read(struct buffer_head *bh) set_buffer_async_read(bh); } -void mark_buffer_async_write(struct buffer_head *bh) +static void mark_buffer_async_write_endio(struct buffer_head *bh, + bh_end_io_t *handler) { - bh->b_end_io = end_buffer_async_write; + bh->b_end_io = handler; set_buffer_async_write(bh); } + +void mark_buffer_async_write(struct buffer_head *bh) +{ + mark_buffer_async_write_endio(bh, end_buffer_async_write); +} EXPORT_SYMBOL(mark_buffer_async_write); @@ -711,9 +503,13 @@ EXPORT_SYMBOL(mark_buffer_async_write); /* * The buffer's backing address_space's private_lock must be held */ -static inline void __remove_assoc_queue(struct buffer_head *bh) +static void __remove_assoc_queue(struct buffer_head *bh) { list_del_init(&bh->b_assoc_buffers); + WARN_ON(!bh->b_assoc_map); + if (buffer_write_io_error(bh)) + set_bit(AS_EIO, &bh->b_assoc_map->flags); + bh->b_assoc_map = NULL; } int inode_has_buffers(struct inode *inode) @@ -756,9 +552,39 @@ repeat: return err; } +static void do_thaw_one(struct super_block *sb, void *unused) +{ + char b[BDEVNAME_SIZE]; + while (sb->s_bdev && !thaw_bdev(sb->s_bdev, sb)) + printk(KERN_WARNING "Emergency Thaw on %s\n", + bdevname(sb->s_bdev, b)); +} + +static void do_thaw_all(struct work_struct *work) +{ + iterate_supers(do_thaw_one, NULL); + kfree(work); + printk(KERN_WARNING "Emergency Thaw complete\n"); +} + /** - * sync_mapping_buffers - write out and wait upon a mapping's "associated" - * buffers + * emergency_thaw_all -- forcibly thaw every frozen filesystem + * + * Used for emergency unfreeze of all filesystems via SysRq + */ +void emergency_thaw_all(void) +{ + struct work_struct *work; + + work = kmalloc(sizeof(*work), GFP_ATOMIC); + if (work) { + INIT_WORK(work, do_thaw_all); + schedule_work(work); + } +} + +/** + * sync_mapping_buffers - write out & wait upon a mapping's "associated" buffers * @mapping: the mapping which wants those buffers written * * Starts I/O against the buffers at mapping->private_list, and waits upon @@ -770,7 +596,7 @@ repeat: */ int sync_mapping_buffers(struct address_space *mapping) { - struct address_space *buffer_mapping = mapping->assoc_mapping; + struct address_space *buffer_mapping = mapping->private_data; if (buffer_mapping == NULL || list_empty(&mapping->private_list)) return 0; @@ -803,22 +629,45 @@ void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode) struct address_space *buffer_mapping = bh->b_page->mapping; mark_buffer_dirty(bh); - if (!mapping->assoc_mapping) { - mapping->assoc_mapping = buffer_mapping; + if (!mapping->private_data) { + mapping->private_data = buffer_mapping; } else { - if (mapping->assoc_mapping != buffer_mapping) - BUG(); + BUG_ON(mapping->private_data != buffer_mapping); } - if (list_empty(&bh->b_assoc_buffers)) { + if (!bh->b_assoc_map) { spin_lock(&buffer_mapping->private_lock); list_move_tail(&bh->b_assoc_buffers, &mapping->private_list); + bh->b_assoc_map = mapping; spin_unlock(&buffer_mapping->private_lock); } } EXPORT_SYMBOL(mark_buffer_dirty_inode); /* + * Mark the page dirty, and set it dirty in the radix tree, and mark the inode + * dirty. + * + * If warn is true, then emit a warning if the page is not uptodate and has + * not been truncated. + */ +static void __set_page_dirty(struct page *page, + struct address_space *mapping, int warn) +{ + unsigned long flags; + + spin_lock_irqsave(&mapping->tree_lock, flags); + if (page->mapping) { /* Race with truncate? */ + WARN_ON_ONCE(warn && !PageUptodate(page)); + account_page_dirtied(page, mapping); + radix_tree_tag_set(&mapping->page_tree, + page_index(page), PAGECACHE_TAG_DIRTY); + } + spin_unlock_irqrestore(&mapping->tree_lock, flags); + __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); +} + +/* * Add a page to the dirty page list. * * It is a sad fact of life that this function is called from several places @@ -845,7 +694,11 @@ EXPORT_SYMBOL(mark_buffer_dirty_inode); */ int __set_page_dirty_buffers(struct page *page) { - struct address_space * const mapping = page->mapping; + int newly_dirty; + struct address_space *mapping = page_mapping(page); + + if (unlikely(!mapping)) + return !TestSetPageDirty(page); spin_lock(&mapping->private_lock); if (page_has_buffers(page)) { @@ -857,22 +710,12 @@ int __set_page_dirty_buffers(struct page *page) bh = bh->b_this_page; } while (bh != head); } + newly_dirty = !TestSetPageDirty(page); spin_unlock(&mapping->private_lock); - if (!TestSetPageDirty(page)) { - write_lock_irq(&mapping->tree_lock); - if (page->mapping) { /* Race with truncate? */ - if (mapping_cap_account_dirty(mapping)) - inc_page_state(nr_dirty); - radix_tree_tag_set(&mapping->page_tree, - page_index(page), - PAGECACHE_TAG_DIRTY); - } - write_unlock_irq(&mapping->tree_lock); - __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); - } - - return 0; + if (newly_dirty) + __set_page_dirty(page, mapping, 1); + return newly_dirty; } EXPORT_SYMBOL(__set_page_dirty_buffers); @@ -899,36 +742,65 @@ static int fsync_buffers_list(spinlock_t *lock, struct list_head *list) { struct buffer_head *bh; struct list_head tmp; + struct address_space *mapping; int err = 0, err2; + struct blk_plug plug; INIT_LIST_HEAD(&tmp); + blk_start_plug(&plug); spin_lock(lock); while (!list_empty(list)) { bh = BH_ENTRY(list->next); - list_del_init(&bh->b_assoc_buffers); + mapping = bh->b_assoc_map; + __remove_assoc_queue(bh); + /* Avoid race with mark_buffer_dirty_inode() which does + * a lockless check and we rely on seeing the dirty bit */ + smp_mb(); if (buffer_dirty(bh) || buffer_locked(bh)) { list_add(&bh->b_assoc_buffers, &tmp); + bh->b_assoc_map = mapping; if (buffer_dirty(bh)) { get_bh(bh); spin_unlock(lock); /* * Ensure any pending I/O completes so that - * ll_rw_block() actually writes the current - * contents - it is a noop if I/O is still in - * flight on potentially older contents. + * write_dirty_buffer() actually writes the + * current contents - it is a noop if I/O is + * still in flight on potentially older + * contents. + */ + write_dirty_buffer(bh, WRITE_SYNC); + + /* + * Kick off IO for the previous mapping. Note + * that we will not run the very last mapping, + * wait_on_buffer() will do that for us + * through sync_buffer(). */ - ll_rw_block(SWRITE, 1, &bh); brelse(bh); spin_lock(lock); } } } + spin_unlock(lock); + blk_finish_plug(&plug); + spin_lock(lock); + while (!list_empty(&tmp)) { bh = BH_ENTRY(tmp.prev); - __remove_assoc_queue(bh); get_bh(bh); + mapping = bh->b_assoc_map; + __remove_assoc_queue(bh); + /* Avoid race with mark_buffer_dirty_inode() which does + * a lockless check and we rely on seeing the dirty bit */ + smp_mb(); + if (buffer_dirty(bh)) { + list_add(&bh->b_assoc_buffers, + &mapping->private_list); + bh->b_assoc_map = mapping; + } spin_unlock(lock); wait_on_buffer(bh); if (!buffer_uptodate(bh)) @@ -959,7 +831,7 @@ void invalidate_inode_buffers(struct inode *inode) if (inode_has_buffers(inode)) { struct address_space *mapping = &inode->i_data; struct list_head *list = &mapping->private_list; - struct address_space *buffer_mapping = mapping->assoc_mapping; + struct address_space *buffer_mapping = mapping->private_data; spin_lock(&buffer_mapping->private_lock); while (!list_empty(list)) @@ -967,6 +839,7 @@ void invalidate_inode_buffers(struct inode *inode) spin_unlock(&buffer_mapping->private_lock); } } +EXPORT_SYMBOL(invalidate_inode_buffers); /* * Remove any clean buffers from the inode's buffer list. This is called @@ -981,7 +854,7 @@ int remove_inode_buffers(struct inode *inode) if (inode_has_buffers(inode)) { struct address_space *mapping = &inode->i_data; struct list_head *list = &mapping->private_list; - struct address_space *buffer_mapping = mapping->assoc_mapping; + struct address_space *buffer_mapping = mapping->private_data; spin_lock(&buffer_mapping->private_lock); while (!list_empty(list)) { @@ -1020,19 +893,14 @@ try_again: if (!bh) goto no_grow; - bh->b_bdev = NULL; bh->b_this_page = head; bh->b_blocknr = -1; head = bh; - bh->b_state = 0; - atomic_set(&bh->b_count, 0); bh->b_size = size; /* Link the buffer to its page */ set_bh_page(bh, page, offset); - - bh->b_end_io = NULL; } return head; /* @@ -1081,16 +949,29 @@ link_dev_buffers(struct page *page, struct buffer_head *head) attach_page_buffers(page, head); } +static sector_t blkdev_max_block(struct block_device *bdev, unsigned int size) +{ + sector_t retval = ~((sector_t)0); + loff_t sz = i_size_read(bdev->bd_inode); + + if (sz) { + unsigned int sizebits = blksize_bits(size); + retval = (sz >> sizebits); + } + return retval; +} + /* * Initialise the state of a blockdev page's buffers. */ -static void +static sector_t init_page_buffers(struct page *page, struct block_device *bdev, sector_t block, int size) { struct buffer_head *head = page_buffers(page); struct buffer_head *bh = head; int uptodate = PageUptodate(page); + sector_t end_block = blkdev_max_block(I_BDEV(bdev->bd_inode), size); do { if (!buffer_mapped(bh)) { @@ -1099,38 +980,57 @@ init_page_buffers(struct page *page, struct block_device *bdev, bh->b_blocknr = block; if (uptodate) set_buffer_uptodate(bh); - set_buffer_mapped(bh); + if (block < end_block) + set_buffer_mapped(bh); } block++; bh = bh->b_this_page; } while (bh != head); + + /* + * Caller needs to validate requested block against end of device. + */ + return end_block; } /* * Create the page-cache page that contains the requested block. * - * This is user purely for blockdev mappings. + * This is used purely for blockdev mappings. */ -static struct page * +static int grow_dev_page(struct block_device *bdev, sector_t block, - pgoff_t index, int size) + pgoff_t index, int size, int sizebits) { struct inode *inode = bdev->bd_inode; struct page *page; struct buffer_head *bh; + sector_t end_block; + int ret = 0; /* Will call free_more_memory() */ + gfp_t gfp_mask; + + gfp_mask = mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS; + gfp_mask |= __GFP_MOVABLE; + /* + * XXX: __getblk_slow() can not really deal with failure and + * will endlessly loop on improvised global reclaim. Prefer + * looping in the allocator rather than here, at least that + * code knows what it's doing. + */ + gfp_mask |= __GFP_NOFAIL; - page = find_or_create_page(inode->i_mapping, index, GFP_NOFS); + page = find_or_create_page(inode->i_mapping, index, gfp_mask); if (!page) - return NULL; + return ret; - if (!PageLocked(page)) - BUG(); + BUG_ON(!PageLocked(page)); if (page_has_buffers(page)) { bh = page_buffers(page); if (bh->b_size == size) { - init_page_buffers(page, bdev, block, size); - return page; + end_block = init_page_buffers(page, bdev, + index << sizebits, size); + goto done; } if (!try_to_free_buffers(page)) goto failed; @@ -1150,30 +1050,23 @@ grow_dev_page(struct block_device *bdev, sector_t block, */ spin_lock(&inode->i_mapping->private_lock); link_dev_buffers(page, bh); - init_page_buffers(page, bdev, block, size); + end_block = init_page_buffers(page, bdev, index << sizebits, size); spin_unlock(&inode->i_mapping->private_lock); - return page; - +done: + ret = (block < end_block) ? 1 : -ENXIO; failed: - BUG(); unlock_page(page); page_cache_release(page); - return NULL; + return ret; } /* * Create buffers for the specified block device block's page. If * that page was dirty, the buffers are set dirty also. - * - * Except that's a bug. Attaching dirty buffers to a dirty - * blockdev's page can result in filesystem corruption, because - * some of those buffers may be aliases of filesystem data. - * grow_dev_page() will go BUG() if this happens. */ -static inline int +static int grow_buffers(struct block_device *bdev, sector_t block, int size) { - struct page *page; pgoff_t index; int sizebits; @@ -1183,40 +1076,52 @@ grow_buffers(struct block_device *bdev, sector_t block, int size) } while ((size << sizebits) < PAGE_SIZE); index = block >> sizebits; - block = index << sizebits; + + /* + * Check for a block which wants to lie outside our maximum possible + * pagecache index. (this comparison is done using sector_t types). + */ + if (unlikely(index != block >> sizebits)) { + char b[BDEVNAME_SIZE]; + + printk(KERN_ERR "%s: requested out-of-range block %llu for " + "device %s\n", + __func__, (unsigned long long)block, + bdevname(bdev, b)); + return -EIO; + } /* Create a page with the proper size buffers.. */ - page = grow_dev_page(bdev, block, index, size); - if (!page) - return 0; - unlock_page(page); - page_cache_release(page); - return 1; + return grow_dev_page(bdev, block, index, size, sizebits); } static struct buffer_head * __getblk_slow(struct block_device *bdev, sector_t block, int size) { /* Size must be multiple of hard sectorsize */ - if (unlikely(size & (bdev_hardsect_size(bdev)-1) || + if (unlikely(size & (bdev_logical_block_size(bdev)-1) || (size < 512 || size > PAGE_SIZE))) { printk(KERN_ERR "getblk(): invalid block size %d requested\n", size); - printk(KERN_ERR "hardsect size: %d\n", - bdev_hardsect_size(bdev)); + printk(KERN_ERR "logical block size: %d\n", + bdev_logical_block_size(bdev)); dump_stack(); return NULL; } for (;;) { - struct buffer_head * bh; + struct buffer_head *bh; + int ret; bh = __find_get_block(bdev, block, size); if (bh) return bh; - if (!grow_buffers(bdev, block, size)) + ret = grow_buffers(bdev, block, size); + if (ret < 0) + return NULL; + if (ret == 0) free_more_memory(); } } @@ -1254,13 +1159,36 @@ __getblk_slow(struct block_device *bdev, sector_t block, int size) * inode list. * * mark_buffer_dirty() is atomic. It takes bh->b_page->mapping->private_lock, - * mapping->tree_lock and the global inode_lock. + * mapping->tree_lock and mapping->host->i_lock. */ -void fastcall mark_buffer_dirty(struct buffer_head *bh) +void mark_buffer_dirty(struct buffer_head *bh) { - if (!buffer_dirty(bh) && !test_set_buffer_dirty(bh)) - __set_page_dirty_nobuffers(bh->b_page); + WARN_ON_ONCE(!buffer_uptodate(bh)); + + trace_block_dirty_buffer(bh); + + /* + * Very *carefully* optimize the it-is-already-dirty case. + * + * Don't let the final "is it dirty" escape to before we + * perhaps modified the buffer. + */ + if (buffer_dirty(bh)) { + smp_mb(); + if (buffer_dirty(bh)) + return; + } + + if (!test_set_buffer_dirty(bh)) { + struct page *page = bh->b_page; + if (!TestSetPageDirty(page)) { + struct address_space *mapping = page_mapping(page); + if (mapping) + __set_page_dirty(page, mapping, 0); + } + } } +EXPORT_SYMBOL(mark_buffer_dirty); /* * Decrement a buffer_head's reference count. If all buffers against a page @@ -1275,9 +1203,9 @@ void __brelse(struct buffer_head * buf) put_bh(buf); return; } - printk(KERN_ERR "VFS: brelse: Trying to free free buffer\n"); - WARN_ON(1); + WARN(1, KERN_ERR "VFS: brelse: Trying to free free buffer\n"); } +EXPORT_SYMBOL(__brelse); /* * bforget() is like brelse(), except it discards any @@ -1286,15 +1214,17 @@ void __brelse(struct buffer_head * buf) void __bforget(struct buffer_head *bh) { clear_buffer_dirty(bh); - if (!list_empty(&bh->b_assoc_buffers)) { + if (bh->b_assoc_map) { struct address_space *buffer_mapping = bh->b_page->mapping; spin_lock(&buffer_mapping->private_lock); list_del_init(&bh->b_assoc_buffers); + bh->b_assoc_map = NULL; spin_unlock(&buffer_mapping->private_lock); } __brelse(bh); } +EXPORT_SYMBOL(__bforget); static struct buffer_head *__bread_slow(struct buffer_head *bh) { @@ -1357,12 +1287,10 @@ static inline void check_irqs_on(void) static void bh_lru_install(struct buffer_head *bh) { struct buffer_head *evictee = NULL; - struct bh_lru *lru; check_irqs_on(); bh_lru_lock(); - lru = &__get_cpu_var(bh_lrus); - if (lru->bhs[0] != bh) { + if (__this_cpu_read(bh_lrus.bhs[0]) != bh) { struct buffer_head *bhs[BH_LRU_SIZE]; int in; int out = 0; @@ -1370,7 +1298,8 @@ static void bh_lru_install(struct buffer_head *bh) get_bh(bh); bhs[out++] = bh; for (in = 0; in < BH_LRU_SIZE; in++) { - struct buffer_head *bh2 = lru->bhs[in]; + struct buffer_head *bh2 = + __this_cpu_read(bh_lrus.bhs[in]); if (bh2 == bh) { __brelse(bh2); @@ -1385,7 +1314,7 @@ static void bh_lru_install(struct buffer_head *bh) } while (out < BH_LRU_SIZE) bhs[out++] = NULL; - memcpy(lru->bhs, bhs, sizeof(bhs)); + memcpy(this_cpu_ptr(&bh_lrus.bhs), bhs, sizeof(bhs)); } bh_lru_unlock(); @@ -1396,27 +1325,26 @@ static void bh_lru_install(struct buffer_head *bh) /* * Look up the bh in this cpu's LRU. If it's there, move it to the head. */ -static inline struct buffer_head * -lookup_bh_lru(struct block_device *bdev, sector_t block, int size) +static struct buffer_head * +lookup_bh_lru(struct block_device *bdev, sector_t block, unsigned size) { struct buffer_head *ret = NULL; - struct bh_lru *lru; - int i; + unsigned int i; check_irqs_on(); bh_lru_lock(); - lru = &__get_cpu_var(bh_lrus); for (i = 0; i < BH_LRU_SIZE; i++) { - struct buffer_head *bh = lru->bhs[i]; + struct buffer_head *bh = __this_cpu_read(bh_lrus.bhs[i]); if (bh && bh->b_bdev == bdev && bh->b_blocknr == block && bh->b_size == size) { if (i) { while (i) { - lru->bhs[i] = lru->bhs[i - 1]; + __this_cpu_write(bh_lrus.bhs[i], + __this_cpu_read(bh_lrus.bhs[i - 1])); i--; } - lru->bhs[0] = bh; + __this_cpu_write(bh_lrus.bhs[0], bh); } get_bh(bh); ret = bh; @@ -1433,17 +1361,18 @@ lookup_bh_lru(struct block_device *bdev, sector_t block, int size) * NULL */ struct buffer_head * -__find_get_block(struct block_device *bdev, sector_t block, int size) +__find_get_block(struct block_device *bdev, sector_t block, unsigned size) { struct buffer_head *bh = lookup_bh_lru(bdev, block, size); if (bh == NULL) { - bh = __find_get_block_slow(bdev, block, size); + /* __find_get_block_slow will mark the page accessed */ + bh = __find_get_block_slow(bdev, block); if (bh) bh_lru_install(bh); - } - if (bh) + } else touch_buffer(bh); + return bh; } EXPORT_SYMBOL(__find_get_block); @@ -1453,15 +1382,11 @@ EXPORT_SYMBOL(__find_get_block); * which corresponds to the passed block_device, block and size. The * returned buffer has its reference count incremented. * - * __getblk() cannot fail - it just keeps trying. If you pass it an - * illegal block number, __getblk() will happily return a buffer_head - * which represents the non-existent block. Very weird. - * * __getblk() will lock up the machine if grow_dev_page's try_to_free_buffers() * attempt is failing. FIXME, perhaps? */ struct buffer_head * -__getblk(struct block_device *bdev, sector_t block, int size) +__getblk(struct block_device *bdev, sector_t block, unsigned size) { struct buffer_head *bh = __find_get_block(bdev, block, size); @@ -1475,11 +1400,13 @@ EXPORT_SYMBOL(__getblk); /* * Do async read-ahead on a buffer.. */ -void __breadahead(struct block_device *bdev, sector_t block, int size) +void __breadahead(struct block_device *bdev, sector_t block, unsigned size) { struct buffer_head *bh = __getblk(bdev, block, size); - ll_rw_block(READA, 1, &bh); - brelse(bh); + if (likely(bh)) { + ll_rw_block(READA, 1, &bh); + brelse(bh); + } } EXPORT_SYMBOL(__breadahead); @@ -1493,11 +1420,11 @@ EXPORT_SYMBOL(__breadahead); * It returns NULL if the block was unreadable. */ struct buffer_head * -__bread(struct block_device *bdev, sector_t block, int size) +__bread(struct block_device *bdev, sector_t block, unsigned size) { struct buffer_head *bh = __getblk(bdev, block, size); - if (!buffer_uptodate(bh)) + if (likely(bh) && !buffer_uptodate(bh)) bh = __bread_slow(bh); return bh; } @@ -1519,18 +1446,31 @@ static void invalidate_bh_lru(void *arg) } put_cpu_var(bh_lrus); } + +static bool has_bh_in_lru(int cpu, void *dummy) +{ + struct bh_lru *b = per_cpu_ptr(&bh_lrus, cpu); + int i; -static void invalidate_bh_lrus(void) + for (i = 0; i < BH_LRU_SIZE; i++) { + if (b->bhs[i]) + return 1; + } + + return 0; +} + +void invalidate_bh_lrus(void) { - on_each_cpu(invalidate_bh_lru, NULL, 1, 1); + on_each_cpu_cond(has_bh_in_lru, invalidate_bh_lru, NULL, 1, GFP_KERNEL); } +EXPORT_SYMBOL_GPL(invalidate_bh_lrus); void set_bh_page(struct buffer_head *bh, struct page *page, unsigned long offset) { bh->b_page = page; - if (offset >= PAGE_SIZE) - BUG(); + BUG_ON(offset >= PAGE_SIZE); if (PageHighMem(page)) /* * This catches illegal uses and preserves the offset: @@ -1544,55 +1484,39 @@ EXPORT_SYMBOL(set_bh_page); /* * Called when truncating a buffer on a page completely. */ -static inline void discard_buffer(struct buffer_head * bh) + +/* Bits that are cleared during an invalidate */ +#define BUFFER_FLAGS_DISCARD \ + (1 << BH_Mapped | 1 << BH_New | 1 << BH_Req | \ + 1 << BH_Delay | 1 << BH_Unwritten) + +static void discard_buffer(struct buffer_head * bh) { + unsigned long b_state, b_state_old; + lock_buffer(bh); clear_buffer_dirty(bh); bh->b_bdev = NULL; - clear_buffer_mapped(bh); - clear_buffer_req(bh); - clear_buffer_new(bh); - clear_buffer_delay(bh); + b_state = bh->b_state; + for (;;) { + b_state_old = cmpxchg(&bh->b_state, b_state, + (b_state & ~BUFFER_FLAGS_DISCARD)); + if (b_state_old == b_state) + break; + b_state = b_state_old; + } unlock_buffer(bh); } /** - * try_to_release_page() - release old fs-specific metadata on a page - * - * @page: the page which the kernel is trying to free - * @gfp_mask: memory allocation flags (and I/O mode) - * - * The address_space is to try to release any data against the page - * (presumably at page->private). If the release was successful, return `1'. - * Otherwise return zero. - * - * The @gfp_mask argument specifies whether I/O may be performed to release - * this page (__GFP_IO), and whether the call may block (__GFP_WAIT). - * - * NOTE: @gfp_mask may go away, and this function may become non-blocking. - */ -int try_to_release_page(struct page *page, gfp_t gfp_mask) -{ - struct address_space * const mapping = page->mapping; - - BUG_ON(!PageLocked(page)); - if (PageWriteback(page)) - return 0; - - if (mapping && mapping->a_ops->releasepage) - return mapping->a_ops->releasepage(page, gfp_mask); - return try_to_free_buffers(page); -} -EXPORT_SYMBOL(try_to_release_page); - -/** - * block_invalidatepage - invalidate part of all of a buffer-backed page + * block_invalidatepage - invalidate part or all of a buffer-backed page * * @page: the page which is affected - * @offset: the index of the truncation point + * @offset: start of the range to invalidate + * @length: length of the range to invalidate * * block_invalidatepage() is called when all or part of the page has become - * invalidatedby a truncate operation. + * invalidated by a truncate operation. * * block_invalidatepage() does not have to release all buffers, but it must * ensure that no dirty buffer is left outside @offset and that no I/O @@ -1600,16 +1524,22 @@ EXPORT_SYMBOL(try_to_release_page); * point. Because the caller is about to free (and possibly reuse) those * blocks on-disk. */ -int block_invalidatepage(struct page *page, unsigned long offset) +void block_invalidatepage(struct page *page, unsigned int offset, + unsigned int length) { struct buffer_head *head, *bh, *next; unsigned int curr_off = 0; - int ret = 1; + unsigned int stop = length + offset; BUG_ON(!PageLocked(page)); if (!page_has_buffers(page)) goto out; + /* + * Check for overflow + */ + BUG_ON(stop > PAGE_CACHE_SIZE || stop < length); + head = page_buffers(page); bh = head; do { @@ -1617,6 +1547,12 @@ int block_invalidatepage(struct page *page, unsigned long offset) next = bh->b_this_page; /* + * Are we still fully in range ? + */ + if (next_off > stop) + goto out; + + /* * is this block fully invalidated? */ if (offset <= curr_off) @@ -1631,12 +1567,13 @@ int block_invalidatepage(struct page *page, unsigned long offset) * so real IO is not possible anymore. */ if (offset == 0) - ret = try_to_release_page(page, 0); + try_to_release_page(page, 0); out: - return ret; + return; } EXPORT_SYMBOL(block_invalidatepage); + /* * We attach and possibly dirty the buffers atomically wrt * __set_page_dirty_buffers() via private_lock. try_to_free_buffers @@ -1694,7 +1631,7 @@ void unmap_underlying_metadata(struct block_device *bdev, sector_t block) might_sleep(); - old_bh = __find_get_block_slow(bdev, block, 0); + old_bh = __find_get_block_slow(bdev, block); if (old_bh) { clear_buffer_dirty(old_bh); wait_on_buffer(old_bh); @@ -1705,6 +1642,28 @@ void unmap_underlying_metadata(struct block_device *bdev, sector_t block) EXPORT_SYMBOL(unmap_underlying_metadata); /* + * Size is a power-of-two in the range 512..PAGE_SIZE, + * and the case we care about most is PAGE_SIZE. + * + * So this *could* possibly be written with those + * constraints in mind (relevant mostly if some + * architecture has a slow bit-scan instruction) + */ +static inline int block_size_bits(unsigned int blocksize) +{ + return ilog2(blocksize); +} + +static struct buffer_head *create_page_buffers(struct page *page, struct inode *inode, unsigned int b_state) +{ + BUG_ON(!PageLocked(page)); + + if (!page_has_buffers(page)) + create_empty_buffers(page, 1 << ACCESS_ONCE(inode->i_blkbits), b_state); + return page_buffers(page); +} + +/* * NOTE! All mapped/uptodate combinations are valid: * * Mapped Uptodate Meaning @@ -1728,24 +1687,26 @@ EXPORT_SYMBOL(unmap_underlying_metadata); * locked buffer. This only can happen if someone has written the buffer * directly, with submit_bh(). At the address_space level PageWriteback * prevents this contention from occurring. + * + * If block_write_full_page() is called with wbc->sync_mode == + * WB_SYNC_ALL, the writes are posted using WRITE_SYNC; this + * causes the writes to be flagged as synchronous writes. */ static int __block_write_full_page(struct inode *inode, struct page *page, - get_block_t *get_block, struct writeback_control *wbc) + get_block_t *get_block, struct writeback_control *wbc, + bh_end_io_t *handler) { int err; sector_t block; sector_t last_block; struct buffer_head *bh, *head; + unsigned int blocksize, bbits; int nr_underway = 0; + int write_op = (wbc->sync_mode == WB_SYNC_ALL ? + WRITE_SYNC : WRITE); - BUG_ON(!PageLocked(page)); - - last_block = (i_size_read(inode) - 1) >> inode->i_blkbits; - - if (!page_has_buffers(page)) { - create_empty_buffers(page, 1 << inode->i_blkbits, + head = create_page_buffers(page, inode, (1 << BH_Dirty)|(1 << BH_Uptodate)); - } /* * Be very careful. We have no exclusion from __set_page_dirty_buffers @@ -1757,9 +1718,12 @@ static int __block_write_full_page(struct inode *inode, struct page *page, * handle that here by just cleaning them. */ - block = page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits); - head = page_buffers(page); bh = head; + blocksize = bh->b_size; + bbits = block_size_bits(blocksize); + + block = (sector_t)page->index << (PAGE_CACHE_SHIFT - bbits); + last_block = (i_size_read(inode) - 1) >> bbits; /* * Get all the dirty buffers mapped to disk addresses and @@ -1777,10 +1741,13 @@ static int __block_write_full_page(struct inode *inode, struct page *page, */ clear_buffer_dirty(bh); set_buffer_uptodate(bh); - } else if (!buffer_mapped(bh) && buffer_dirty(bh)) { + } else if ((!buffer_mapped(bh) || buffer_delay(bh)) && + buffer_dirty(bh)) { + WARN_ON(bh->b_size != blocksize); err = get_block(inode, block, bh, 1); if (err) goto recover; + clear_buffer_delay(bh); if (buffer_new(bh)) { /* blockdev mappings never come here */ clear_buffer_new(bh); @@ -1798,18 +1765,18 @@ static int __block_write_full_page(struct inode *inode, struct page *page, /* * If it's a fully non-blocking write attempt and we cannot * lock the buffer then redirty the page. Note that this can - * potentially cause a busy-wait loop from pdflush and kswapd - * activity, but those code paths have their own higher-level - * throttling. + * potentially cause a busy-wait loop from writeback threads + * and kswapd activity, but those code paths have their own + * higher-level throttling. */ - if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) { + if (wbc->sync_mode != WB_SYNC_NONE) { lock_buffer(bh); - } else if (test_set_buffer_locked(bh)) { + } else if (!trylock_buffer(bh)) { redirty_page_for_writepage(wbc, page); continue; } if (test_clear_buffer_dirty(bh)) { - mark_buffer_async_write(bh); + mark_buffer_async_write_endio(bh, handler); } else { unlock_buffer(bh); } @@ -1825,7 +1792,7 @@ static int __block_write_full_page(struct inode *inode, struct page *page, do { struct buffer_head *next = bh->b_this_page; if (buffer_async_write(bh)) { - submit_bh(WRITE, bh); + submit_bh(write_op, bh); nr_underway++; } bh = next; @@ -1840,22 +1807,12 @@ done: * clean. Someone wrote them back by hand with * ll_rw_block/submit_bh. A rare case. */ - int uptodate = 1; - do { - if (!buffer_uptodate(bh)) { - uptodate = 0; - break; - } - bh = bh->b_this_page; - } while (bh != head); - if (uptodate) - SetPageUptodate(page); end_page_writeback(page); + /* * The page and buffer_heads can be released at any time from * here on. */ - wbc->pages_skipped++; /* We didn't write this page */ } return err; @@ -1869,9 +1826,10 @@ recover: bh = head; /* Recovery: lock and submit the mapped buffers */ do { - if (buffer_mapped(bh) && buffer_dirty(bh)) { + if (buffer_mapped(bh) && buffer_dirty(bh) && + !buffer_delay(bh)) { lock_buffer(bh); - mark_buffer_async_write(bh); + mark_buffer_async_write_endio(bh, handler); } else { /* * The buffer may have been set dirty during @@ -1882,23 +1840,69 @@ recover: } while ((bh = bh->b_this_page) != head); SetPageError(page); BUG_ON(PageWriteback(page)); + mapping_set_error(page->mapping, err); set_page_writeback(page); - unlock_page(page); do { struct buffer_head *next = bh->b_this_page; if (buffer_async_write(bh)) { clear_buffer_dirty(bh); - submit_bh(WRITE, bh); + submit_bh(write_op, bh); nr_underway++; } bh = next; } while (bh != head); + unlock_page(page); goto done; } -static int __block_prepare_write(struct inode *inode, struct page *page, - unsigned from, unsigned to, get_block_t *get_block) +/* + * If a page has any new buffers, zero them out here, and mark them uptodate + * and dirty so they'll be written out (in order to prevent uninitialised + * block data from leaking). And clear the new bit. + */ +void page_zero_new_buffers(struct page *page, unsigned from, unsigned to) +{ + unsigned int block_start, block_end; + struct buffer_head *head, *bh; + + BUG_ON(!PageLocked(page)); + if (!page_has_buffers(page)) + return; + + bh = head = page_buffers(page); + block_start = 0; + do { + block_end = block_start + bh->b_size; + + if (buffer_new(bh)) { + if (block_end > from && block_start < to) { + if (!PageUptodate(page)) { + unsigned start, size; + + start = max(from, block_start); + size = min(to, block_end) - start; + + zero_user(page, start, size); + set_buffer_uptodate(bh); + } + + clear_buffer_new(bh); + mark_buffer_dirty(bh); + } + } + + block_start = block_end; + bh = bh->b_this_page; + } while (bh != head); +} +EXPORT_SYMBOL(page_zero_new_buffers); + +int __block_write_begin(struct page *page, loff_t pos, unsigned len, + get_block_t *get_block) { + unsigned from = pos & (PAGE_CACHE_SIZE - 1); + unsigned to = from + len; + struct inode *inode = page->mapping->host; unsigned block_start, block_end; sector_t block; int err = 0; @@ -1910,12 +1914,10 @@ static int __block_prepare_write(struct inode *inode, struct page *page, BUG_ON(to > PAGE_CACHE_SIZE); BUG_ON(from > to); - blocksize = 1 << inode->i_blkbits; - if (!page_has_buffers(page)) - create_empty_buffers(page, blocksize, 0); - head = page_buffers(page); + head = create_page_buffers(page, inode, 0); + blocksize = head->b_size; + bbits = block_size_bits(blocksize); - bbits = inode->i_blkbits; block = (sector_t)page->index << (PAGE_CACHE_SHIFT - bbits); for(bh = head, block_start = 0; bh != head || !block_start; @@ -1931,6 +1933,7 @@ static int __block_prepare_write(struct inode *inode, struct page *page, if (buffer_new(bh)) clear_buffer_new(bh); if (!buffer_mapped(bh)) { + WARN_ON(bh->b_size != blocksize); err = get_block(inode, block, bh, 1); if (err) break; @@ -1938,22 +1941,15 @@ static int __block_prepare_write(struct inode *inode, struct page *page, unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr); if (PageUptodate(page)) { + clear_buffer_new(bh); set_buffer_uptodate(bh); + mark_buffer_dirty(bh); continue; } - if (block_end > to || block_start < from) { - void *kaddr; - - kaddr = kmap_atomic(page, KM_USER0); - if (block_end > to) - memset(kaddr+to, 0, - block_end-to); - if (block_start < from) - memset(kaddr+block_start, - 0, from-block_start); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); - } + if (block_end > to || block_start < from) + zero_user_segments(page, + to, block_end, + block_start, from); continue; } } @@ -1963,6 +1959,7 @@ static int __block_prepare_write(struct inode *inode, struct page *page, continue; } if (!buffer_uptodate(bh) && !buffer_delay(bh) && + !buffer_unwritten(bh) && (block_start < from || block_end > to)) { ll_rw_block(READ, 1, &bh); *wait_bh++=bh; @@ -1976,44 +1973,11 @@ static int __block_prepare_write(struct inode *inode, struct page *page, if (!buffer_uptodate(*wait_bh)) err = -EIO; } - if (!err) { - bh = head; - do { - if (buffer_new(bh)) - clear_buffer_new(bh); - } while ((bh = bh->b_this_page) != head); - return 0; - } - /* Error case: */ - /* - * Zero out any newly allocated blocks to avoid exposing stale - * data. If BH_New is set, we know that the block was newly - * allocated in the above loop. - */ - bh = head; - block_start = 0; - do { - block_end = block_start+blocksize; - if (block_end <= from) - goto next_bh; - if (block_start >= to) - break; - if (buffer_new(bh)) { - void *kaddr; - - clear_buffer_new(bh); - kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr+block_start, 0, bh->b_size); - kunmap_atomic(kaddr, KM_USER0); - set_buffer_uptodate(bh); - mark_buffer_dirty(bh); - } -next_bh: - block_start = block_end; - bh = bh->b_this_page; - } while (bh != head); + if (unlikely(err)) + page_zero_new_buffers(page, from, to); return err; } +EXPORT_SYMBOL(__block_write_begin); static int __block_commit_write(struct inode *inode, struct page *page, unsigned from, unsigned to) @@ -2023,11 +1987,11 @@ static int __block_commit_write(struct inode *inode, struct page *page, unsigned blocksize; struct buffer_head *bh, *head; - blocksize = 1 << inode->i_blkbits; + bh = head = page_buffers(page); + blocksize = bh->b_size; - for(bh = head = page_buffers(page), block_start = 0; - bh != head || !block_start; - block_start=block_end, bh = bh->b_this_page) { + block_start = 0; + do { block_end = block_start + blocksize; if (block_end <= from || block_start >= to) { if (!buffer_uptodate(bh)) @@ -2036,7 +2000,11 @@ static int __block_commit_write(struct inode *inode, struct page *page, set_buffer_uptodate(bh); mark_buffer_dirty(bh); } - } + clear_buffer_new(bh); + + block_start = block_end; + bh = bh->b_this_page; + } while (bh != head); /* * If this is a partial write which happened to make all buffers @@ -2050,6 +2018,153 @@ static int __block_commit_write(struct inode *inode, struct page *page, } /* + * block_write_begin takes care of the basic task of block allocation and + * bringing partial write blocks uptodate first. + * + * The filesystem needs to handle block truncation upon failure. + */ +int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len, + unsigned flags, struct page **pagep, get_block_t *get_block) +{ + pgoff_t index = pos >> PAGE_CACHE_SHIFT; + struct page *page; + int status; + + page = grab_cache_page_write_begin(mapping, index, flags); + if (!page) + return -ENOMEM; + + status = __block_write_begin(page, pos, len, get_block); + if (unlikely(status)) { + unlock_page(page); + page_cache_release(page); + page = NULL; + } + + *pagep = page; + return status; +} +EXPORT_SYMBOL(block_write_begin); + +int block_write_end(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct page *page, void *fsdata) +{ + struct inode *inode = mapping->host; + unsigned start; + + start = pos & (PAGE_CACHE_SIZE - 1); + + if (unlikely(copied < len)) { + /* + * The buffers that were written will now be uptodate, so we + * don't have to worry about a readpage reading them and + * overwriting a partial write. However if we have encountered + * a short write and only partially written into a buffer, it + * will not be marked uptodate, so a readpage might come in and + * destroy our partial write. + * + * Do the simplest thing, and just treat any short write to a + * non uptodate page as a zero-length write, and force the + * caller to redo the whole thing. + */ + if (!PageUptodate(page)) + copied = 0; + + page_zero_new_buffers(page, start+copied, start+len); + } + flush_dcache_page(page); + + /* This could be a short (even 0-length) commit */ + __block_commit_write(inode, page, start, start+copied); + + return copied; +} +EXPORT_SYMBOL(block_write_end); + +int generic_write_end(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct page *page, void *fsdata) +{ + struct inode *inode = mapping->host; + int i_size_changed = 0; + + copied = block_write_end(file, mapping, pos, len, copied, page, fsdata); + + /* + * No need to use i_size_read() here, the i_size + * cannot change under us because we hold i_mutex. + * + * But it's important to update i_size while still holding page lock: + * page writeout could otherwise come in and zero beyond i_size. + */ + if (pos+copied > inode->i_size) { + i_size_write(inode, pos+copied); + i_size_changed = 1; + } + + unlock_page(page); + page_cache_release(page); + + /* + * Don't mark the inode dirty under page lock. First, it unnecessarily + * makes the holding time of page lock longer. Second, it forces lock + * ordering of page lock and transaction start for journaling + * filesystems. + */ + if (i_size_changed) + mark_inode_dirty(inode); + + return copied; +} +EXPORT_SYMBOL(generic_write_end); + +/* + * block_is_partially_uptodate checks whether buffers within a page are + * uptodate or not. + * + * Returns true if all buffers which correspond to a file portion + * we want to read are uptodate. + */ +int block_is_partially_uptodate(struct page *page, unsigned long from, + unsigned long count) +{ + unsigned block_start, block_end, blocksize; + unsigned to; + struct buffer_head *bh, *head; + int ret = 1; + + if (!page_has_buffers(page)) + return 0; + + head = page_buffers(page); + blocksize = head->b_size; + to = min_t(unsigned, PAGE_CACHE_SIZE - from, count); + to = from + to; + if (from < blocksize && to > PAGE_CACHE_SIZE - blocksize) + return 0; + + bh = head; + block_start = 0; + do { + block_end = block_start + blocksize; + if (block_end > from && block_start < to) { + if (!buffer_uptodate(bh)) { + ret = 0; + break; + } + if (block_end >= to) + break; + } + block_start = block_end; + bh = bh->b_this_page; + } while (bh != head); + + return ret; +} +EXPORT_SYMBOL(block_is_partially_uptodate); + +/* * Generic "read page" function for block devices that have the normal * get_block functionality. This is most of the block device filesystems. * Reads the page asynchronously --- the unlock_buffer() and @@ -2061,18 +2176,16 @@ int block_read_full_page(struct page *page, get_block_t *get_block) struct inode *inode = page->mapping->host; sector_t iblock, lblock; struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE]; - unsigned int blocksize; + unsigned int blocksize, bbits; int nr, i; int fully_mapped = 1; - BUG_ON(!PageLocked(page)); - blocksize = 1 << inode->i_blkbits; - if (!page_has_buffers(page)) - create_empty_buffers(page, blocksize, 0); - head = page_buffers(page); + head = create_page_buffers(page, inode, 0); + blocksize = head->b_size; + bbits = block_size_bits(blocksize); - iblock = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits); - lblock = (i_size_read(inode)+blocksize-1) >> inode->i_blkbits; + iblock = (sector_t)page->index << (PAGE_CACHE_SHIFT - bbits); + lblock = (i_size_read(inode)+blocksize-1) >> bbits; bh = head; nr = 0; i = 0; @@ -2086,15 +2199,13 @@ int block_read_full_page(struct page *page, get_block_t *get_block) fully_mapped = 0; if (iblock < lblock) { + WARN_ON(bh->b_size != blocksize); err = get_block(inode, iblock, bh, 0); if (err) SetPageError(page); } if (!buffer_mapped(bh)) { - void *kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr + i * blocksize, 0, blocksize); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); + zero_user(page, i * blocksize, blocksize); if (!err) set_buffer_uptodate(bh); continue; @@ -2144,148 +2255,133 @@ int block_read_full_page(struct page *page, get_block_t *get_block) } return 0; } +EXPORT_SYMBOL(block_read_full_page); /* utility function for filesystems that need to do work on expanding - * truncates. Uses prepare/commit_write to allow the filesystem to + * truncates. Uses filesystem pagecache writes to allow the filesystem to * deal with the hole. */ -int generic_cont_expand(struct inode *inode, loff_t size) +int generic_cont_expand_simple(struct inode *inode, loff_t size) { struct address_space *mapping = inode->i_mapping; struct page *page; - unsigned long index, offset, limit; + void *fsdata; int err; - err = -EFBIG; - limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; - if (limit != RLIM_INFINITY && size > (loff_t)limit) { - send_sig(SIGXFSZ, current, 0); + err = inode_newsize_ok(inode, size); + if (err) goto out; - } - if (size > inode->i_sb->s_maxbytes) + + err = pagecache_write_begin(NULL, mapping, size, 0, + AOP_FLAG_UNINTERRUPTIBLE|AOP_FLAG_CONT_EXPAND, + &page, &fsdata); + if (err) goto out; - offset = (size & (PAGE_CACHE_SIZE-1)); /* Within page */ + err = pagecache_write_end(NULL, mapping, size, 0, 0, page, fsdata); + BUG_ON(err > 0); - /* ugh. in prepare/commit_write, if from==to==start of block, we - ** skip the prepare. make sure we never send an offset for the start - ** of a block - */ - if ((offset & (inode->i_sb->s_blocksize - 1)) == 0) { - offset++; - } - index = size >> PAGE_CACHE_SHIFT; - err = -ENOMEM; - page = grab_cache_page(mapping, index); - if (!page) - goto out; - err = mapping->a_ops->prepare_write(NULL, page, offset, offset); - if (!err) { - err = mapping->a_ops->commit_write(NULL, page, offset, offset); - } - unlock_page(page); - page_cache_release(page); - if (err > 0) - err = 0; out: return err; } +EXPORT_SYMBOL(generic_cont_expand_simple); -/* - * For moronic filesystems that do not allow holes in file. - * We may have to extend the file. - */ - -int cont_prepare_write(struct page *page, unsigned offset, - unsigned to, get_block_t *get_block, loff_t *bytes) +static int cont_expand_zero(struct file *file, struct address_space *mapping, + loff_t pos, loff_t *bytes) { - struct address_space *mapping = page->mapping; struct inode *inode = mapping->host; - struct page *new_page; - pgoff_t pgpos; - long status; - unsigned zerofrom; unsigned blocksize = 1 << inode->i_blkbits; - void *kaddr; + struct page *page; + void *fsdata; + pgoff_t index, curidx; + loff_t curpos; + unsigned zerofrom, offset, len; + int err = 0; - while(page->index > (pgpos = *bytes>>PAGE_CACHE_SHIFT)) { - status = -ENOMEM; - new_page = grab_cache_page(mapping, pgpos); - if (!new_page) - goto out; - /* we might sleep */ - if (*bytes>>PAGE_CACHE_SHIFT != pgpos) { - unlock_page(new_page); - page_cache_release(new_page); - continue; - } - zerofrom = *bytes & ~PAGE_CACHE_MASK; + index = pos >> PAGE_CACHE_SHIFT; + offset = pos & ~PAGE_CACHE_MASK; + + while (index > (curidx = (curpos = *bytes)>>PAGE_CACHE_SHIFT)) { + zerofrom = curpos & ~PAGE_CACHE_MASK; if (zerofrom & (blocksize-1)) { *bytes |= (blocksize-1); (*bytes)++; } - status = __block_prepare_write(inode, new_page, zerofrom, - PAGE_CACHE_SIZE, get_block); - if (status) - goto out_unmap; - kaddr = kmap_atomic(new_page, KM_USER0); - memset(kaddr+zerofrom, 0, PAGE_CACHE_SIZE-zerofrom); - flush_dcache_page(new_page); - kunmap_atomic(kaddr, KM_USER0); - generic_commit_write(NULL, new_page, zerofrom, PAGE_CACHE_SIZE); - unlock_page(new_page); - page_cache_release(new_page); - } - - if (page->index < pgpos) { - /* completely inside the area */ - zerofrom = offset; - } else { - /* page covers the boundary, find the boundary offset */ - zerofrom = *bytes & ~PAGE_CACHE_MASK; + len = PAGE_CACHE_SIZE - zerofrom; + + err = pagecache_write_begin(file, mapping, curpos, len, + AOP_FLAG_UNINTERRUPTIBLE, + &page, &fsdata); + if (err) + goto out; + zero_user(page, zerofrom, len); + err = pagecache_write_end(file, mapping, curpos, len, len, + page, fsdata); + if (err < 0) + goto out; + BUG_ON(err != len); + err = 0; + balance_dirty_pages_ratelimited(mapping); + } + + /* page covers the boundary, find the boundary offset */ + if (index == curidx) { + zerofrom = curpos & ~PAGE_CACHE_MASK; /* if we will expand the thing last block will be filled */ - if (to > zerofrom && (zerofrom & (blocksize-1))) { + if (offset <= zerofrom) { + goto out; + } + if (zerofrom & (blocksize-1)) { *bytes |= (blocksize-1); (*bytes)++; } + len = offset - zerofrom; - /* starting below the boundary? Nothing to zero out */ - if (offset <= zerofrom) - zerofrom = offset; - } - status = __block_prepare_write(inode, page, zerofrom, to, get_block); - if (status) - goto out1; - if (zerofrom < offset) { - kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr+zerofrom, 0, offset-zerofrom); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); - __block_commit_write(inode, page, zerofrom, offset); + err = pagecache_write_begin(file, mapping, curpos, len, + AOP_FLAG_UNINTERRUPTIBLE, + &page, &fsdata); + if (err) + goto out; + zero_user(page, zerofrom, len); + err = pagecache_write_end(file, mapping, curpos, len, len, + page, fsdata); + if (err < 0) + goto out; + BUG_ON(err != len); + err = 0; } - return 0; -out1: - ClearPageUptodate(page); - return status; - -out_unmap: - ClearPageUptodate(new_page); - unlock_page(new_page); - page_cache_release(new_page); out: - return status; + return err; } -int block_prepare_write(struct page *page, unsigned from, unsigned to, - get_block_t *get_block) +/* + * For moronic filesystems that do not allow holes in file. + * We may have to extend the file. + */ +int cont_write_begin(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned flags, + struct page **pagep, void **fsdata, + get_block_t *get_block, loff_t *bytes) { - struct inode *inode = page->mapping->host; - int err = __block_prepare_write(inode, page, from, to, get_block); + struct inode *inode = mapping->host; + unsigned blocksize = 1 << inode->i_blkbits; + unsigned zerofrom; + int err; + + err = cont_expand_zero(file, mapping, pos, bytes); if (err) - ClearPageUptodate(page); - return err; + return err; + + zerofrom = *bytes & ~PAGE_CACHE_MASK; + if (pos+len > *bytes && zerofrom & (blocksize-1)) { + *bytes |= (blocksize-1); + (*bytes)++; + } + + return block_write_begin(mapping, pos, len, flags, pagep, get_block); } +EXPORT_SYMBOL(cont_write_begin); int block_commit_write(struct page *page, unsigned from, unsigned to) { @@ -2293,157 +2389,232 @@ int block_commit_write(struct page *page, unsigned from, unsigned to) __block_commit_write(inode,page,from,to); return 0; } +EXPORT_SYMBOL(block_commit_write); -int generic_commit_write(struct file *file, struct page *page, - unsigned from, unsigned to) +/* + * block_page_mkwrite() is not allowed to change the file size as it gets + * called from a page fault handler when a page is first dirtied. Hence we must + * be careful to check for EOF conditions here. We set the page up correctly + * for a written page which means we get ENOSPC checking when writing into + * holes and correct delalloc and unwritten extent mapping on filesystems that + * support these features. + * + * We are not allowed to take the i_mutex here so we have to play games to + * protect against truncate races as the page could now be beyond EOF. Because + * truncate writes the inode size before removing pages, once we have the + * page lock we can determine safely if the page is beyond EOF. If it is not + * beyond EOF, then the page is guaranteed safe against truncation until we + * unlock the page. + * + * Direct callers of this function should protect against filesystem freezing + * using sb_start_write() - sb_end_write() functions. + */ +int __block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, + get_block_t get_block) { - struct inode *inode = page->mapping->host; - loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to; - __block_commit_write(inode,page,from,to); - /* - * No need to use i_size_read() here, the i_size - * cannot change under us because we hold i_sem. - */ - if (pos > inode->i_size) { - i_size_write(inode, pos); - mark_inode_dirty(inode); + struct page *page = vmf->page; + struct inode *inode = file_inode(vma->vm_file); + unsigned long end; + loff_t size; + int ret; + + lock_page(page); + size = i_size_read(inode); + if ((page->mapping != inode->i_mapping) || + (page_offset(page) > size)) { + /* We overload EFAULT to mean page got truncated */ + ret = -EFAULT; + goto out_unlock; } + + /* page is wholly or partially inside EOF */ + if (((page->index + 1) << PAGE_CACHE_SHIFT) > size) + end = size & ~PAGE_CACHE_MASK; + else + end = PAGE_CACHE_SIZE; + + ret = __block_write_begin(page, 0, end, get_block); + if (!ret) + ret = block_commit_write(page, 0, end); + + if (unlikely(ret < 0)) + goto out_unlock; + set_page_dirty(page); + wait_for_stable_page(page); return 0; +out_unlock: + unlock_page(page); + return ret; } +EXPORT_SYMBOL(__block_page_mkwrite); +int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf, + get_block_t get_block) +{ + int ret; + struct super_block *sb = file_inode(vma->vm_file)->i_sb; + + sb_start_pagefault(sb); + + /* + * Update file times before taking page lock. We may end up failing the + * fault so this update may be superfluous but who really cares... + */ + file_update_time(vma->vm_file); + + ret = __block_page_mkwrite(vma, vmf, get_block); + sb_end_pagefault(sb); + return block_page_mkwrite_return(ret); +} +EXPORT_SYMBOL(block_page_mkwrite); /* - * nobh_prepare_write()'s prereads are special: the buffer_heads are freed + * nobh_write_begin()'s prereads are special: the buffer_heads are freed * immediately, while under the page lock. So it needs a special end_io * handler which does not touch the bh after unlocking it. - * - * Note: unlock_buffer() sort-of does touch the bh after unlocking it, but - * a race there is benign: unlock_buffer() only use the bh's address for - * hashing after unlocking the buffer, so it doesn't actually touch the bh - * itself. */ static void end_buffer_read_nobh(struct buffer_head *bh, int uptodate) { - if (uptodate) { - set_buffer_uptodate(bh); - } else { - /* This happens, due to failed READA attempts. */ - clear_buffer_uptodate(bh); - } - unlock_buffer(bh); + __end_buffer_read_notouch(bh, uptodate); +} + +/* + * Attach the singly-linked list of buffers created by nobh_write_begin, to + * the page (converting it to circular linked list and taking care of page + * dirty races). + */ +static void attach_nobh_buffers(struct page *page, struct buffer_head *head) +{ + struct buffer_head *bh; + + BUG_ON(!PageLocked(page)); + + spin_lock(&page->mapping->private_lock); + bh = head; + do { + if (PageDirty(page)) + set_buffer_dirty(bh); + if (!bh->b_this_page) + bh->b_this_page = head; + bh = bh->b_this_page; + } while (bh != head); + attach_page_buffers(page, head); + spin_unlock(&page->mapping->private_lock); } /* * On entry, the page is fully not uptodate. * On exit the page is fully uptodate in the areas outside (from,to) + * The filesystem needs to handle block truncation upon failure. */ -int nobh_prepare_write(struct page *page, unsigned from, unsigned to, +int nobh_write_begin(struct address_space *mapping, + loff_t pos, unsigned len, unsigned flags, + struct page **pagep, void **fsdata, get_block_t *get_block) { - struct inode *inode = page->mapping->host; + struct inode *inode = mapping->host; const unsigned blkbits = inode->i_blkbits; const unsigned blocksize = 1 << blkbits; - struct buffer_head map_bh; - struct buffer_head *read_bh[MAX_BUF_PER_PAGE]; + struct buffer_head *head, *bh; + struct page *page; + pgoff_t index; + unsigned from, to; unsigned block_in_page; - unsigned block_start; + unsigned block_start, block_end; sector_t block_in_file; - char *kaddr; int nr_reads = 0; - int i; int ret = 0; int is_mapped_to_disk = 1; - int dirtied_it = 0; + + index = pos >> PAGE_CACHE_SHIFT; + from = pos & (PAGE_CACHE_SIZE - 1); + to = from + len; + + page = grab_cache_page_write_begin(mapping, index, flags); + if (!page) + return -ENOMEM; + *pagep = page; + *fsdata = NULL; + + if (page_has_buffers(page)) { + ret = __block_write_begin(page, pos, len, get_block); + if (unlikely(ret)) + goto out_release; + return ret; + } if (PageMappedToDisk(page)) return 0; + /* + * Allocate buffers so that we can keep track of state, and potentially + * attach them to the page if an error occurs. In the common case of + * no error, they will just be freed again without ever being attached + * to the page (which is all OK, because we're under the page lock). + * + * Be careful: the buffer linked list is a NULL terminated one, rather + * than the circular one we're used to. + */ + head = alloc_page_buffers(page, blocksize, 0); + if (!head) { + ret = -ENOMEM; + goto out_release; + } + block_in_file = (sector_t)page->index << (PAGE_CACHE_SHIFT - blkbits); - map_bh.b_page = page; /* * We loop across all blocks in the page, whether or not they are * part of the affected region. This is so we can discover if the * page is fully mapped-to-disk. */ - for (block_start = 0, block_in_page = 0; + for (block_start = 0, block_in_page = 0, bh = head; block_start < PAGE_CACHE_SIZE; - block_in_page++, block_start += blocksize) { - unsigned block_end = block_start + blocksize; + block_in_page++, block_start += blocksize, bh = bh->b_this_page) { int create; - map_bh.b_state = 0; + block_end = block_start + blocksize; + bh->b_state = 0; create = 1; if (block_start >= to) create = 0; ret = get_block(inode, block_in_file + block_in_page, - &map_bh, create); + bh, create); if (ret) goto failed; - if (!buffer_mapped(&map_bh)) + if (!buffer_mapped(bh)) is_mapped_to_disk = 0; - if (buffer_new(&map_bh)) - unmap_underlying_metadata(map_bh.b_bdev, - map_bh.b_blocknr); - if (PageUptodate(page)) + if (buffer_new(bh)) + unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr); + if (PageUptodate(page)) { + set_buffer_uptodate(bh); continue; - if (buffer_new(&map_bh) || !buffer_mapped(&map_bh)) { - kaddr = kmap_atomic(page, KM_USER0); - if (block_start < from) { - memset(kaddr+block_start, 0, from-block_start); - dirtied_it = 1; - } - if (block_end > to) { - memset(kaddr + to, 0, block_end - to); - dirtied_it = 1; - } - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); + } + if (buffer_new(bh) || !buffer_mapped(bh)) { + zero_user_segments(page, block_start, from, + to, block_end); continue; } - if (buffer_uptodate(&map_bh)) + if (buffer_uptodate(bh)) continue; /* reiserfs does this */ if (block_start < from || block_end > to) { - struct buffer_head *bh = alloc_buffer_head(GFP_NOFS); - - if (!bh) { - ret = -ENOMEM; - goto failed; - } - bh->b_state = map_bh.b_state; - atomic_set(&bh->b_count, 0); - bh->b_this_page = NULL; - bh->b_page = page; - bh->b_blocknr = map_bh.b_blocknr; - bh->b_size = blocksize; - bh->b_data = (char *)(long)block_start; - bh->b_bdev = map_bh.b_bdev; - bh->b_private = NULL; - read_bh[nr_reads++] = bh; + lock_buffer(bh); + bh->b_end_io = end_buffer_read_nobh; + submit_bh(READ, bh); + nr_reads++; } } if (nr_reads) { - struct buffer_head *bh; - /* * The page is locked, so these buffers are protected from * any VM or truncate activity. Hence we don't need to care * for the buffer_head refcounts. */ - for (i = 0; i < nr_reads; i++) { - bh = read_bh[i]; - lock_buffer(bh); - bh->b_end_io = end_buffer_read_nobh; - submit_bh(READ, bh); - } - for (i = 0; i < nr_reads; i++) { - bh = read_bh[i]; + for (bh = head; bh; bh = bh->b_this_page) { wait_on_buffer(bh); if (!buffer_uptodate(bh)) ret = -EIO; - free_buffer_head(bh); - read_bh[i] = NULL; } if (ret) goto failed; @@ -2451,53 +2622,66 @@ int nobh_prepare_write(struct page *page, unsigned from, unsigned to, if (is_mapped_to_disk) SetPageMappedToDisk(page); - SetPageUptodate(page); - /* - * Setting the page dirty here isn't necessary for the prepare_write - * function - commit_write will do that. But if/when this function is - * used within the pagefault handler to ensure that all mmapped pages - * have backing space in the filesystem, we will need to dirty the page - * if its contents were altered. - */ - if (dirtied_it) - set_page_dirty(page); + *fsdata = head; /* to be released by nobh_write_end */ return 0; failed: - for (i = 0; i < nr_reads; i++) { - if (read_bh[i]) - free_buffer_head(read_bh[i]); - } - + BUG_ON(!ret); /* - * Error recovery is pretty slack. Clear the page and mark it dirty - * so we'll later zero out any blocks which _were_ allocated. + * Error recovery is a bit difficult. We need to zero out blocks that + * were newly allocated, and dirty them to ensure they get written out. + * Buffers need to be attached to the page at this point, otherwise + * the handling of potential IO errors during writeout would be hard + * (could try doing synchronous writeout, but what if that fails too?) */ - kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr, 0, PAGE_CACHE_SIZE); - kunmap_atomic(kaddr, KM_USER0); - SetPageUptodate(page); - set_page_dirty(page); + attach_nobh_buffers(page, head); + page_zero_new_buffers(page, from, to); + +out_release: + unlock_page(page); + page_cache_release(page); + *pagep = NULL; + return ret; } -EXPORT_SYMBOL(nobh_prepare_write); +EXPORT_SYMBOL(nobh_write_begin); -int nobh_commit_write(struct file *file, struct page *page, - unsigned from, unsigned to) +int nobh_write_end(struct file *file, struct address_space *mapping, + loff_t pos, unsigned len, unsigned copied, + struct page *page, void *fsdata) { struct inode *inode = page->mapping->host; - loff_t pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to; + struct buffer_head *head = fsdata; + struct buffer_head *bh; + BUG_ON(fsdata != NULL && page_has_buffers(page)); + + if (unlikely(copied < len) && head) + attach_nobh_buffers(page, head); + if (page_has_buffers(page)) + return generic_write_end(file, mapping, pos, len, + copied, page, fsdata); + SetPageUptodate(page); set_page_dirty(page); - if (pos > inode->i_size) { - i_size_write(inode, pos); + if (pos+copied > inode->i_size) { + i_size_write(inode, pos+copied); mark_inode_dirty(inode); } - return 0; + + unlock_page(page); + page_cache_release(page); + + while (head) { + bh = head; + head = head->b_this_page; + free_buffer_head(bh); + } + + return copied; } -EXPORT_SYMBOL(nobh_commit_write); +EXPORT_SYMBOL(nobh_write_end); /* * nobh_writepage() - based on block_full_write_page() except @@ -2511,7 +2695,6 @@ int nobh_writepage(struct page *page, get_block_t *get_block, loff_t i_size = i_size_read(inode); const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT; unsigned offset; - void *kaddr; int ret; /* Is the page fully inside i_size? */ @@ -2542,54 +2725,91 @@ int nobh_writepage(struct page *page, get_block_t *get_block, * the page size, the remaining memory is zeroed when mapped, and * writes to that region are not written out to the file." */ - kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); + zero_user_segment(page, offset, PAGE_CACHE_SIZE); out: ret = mpage_writepage(page, get_block, wbc); if (ret == -EAGAIN) - ret = __block_write_full_page(inode, page, get_block, wbc); + ret = __block_write_full_page(inode, page, get_block, wbc, + end_buffer_async_write); return ret; } EXPORT_SYMBOL(nobh_writepage); -/* - * This function assumes that ->prepare_write() uses nobh_prepare_write(). - */ -int nobh_truncate_page(struct address_space *mapping, loff_t from) +int nobh_truncate_page(struct address_space *mapping, + loff_t from, get_block_t *get_block) { - struct inode *inode = mapping->host; - unsigned blocksize = 1 << inode->i_blkbits; pgoff_t index = from >> PAGE_CACHE_SHIFT; unsigned offset = from & (PAGE_CACHE_SIZE-1); - unsigned to; + unsigned blocksize; + sector_t iblock; + unsigned length, pos; + struct inode *inode = mapping->host; struct page *page; - struct address_space_operations *a_ops = mapping->a_ops; - char *kaddr; - int ret = 0; + struct buffer_head map_bh; + int err; - if ((offset & (blocksize - 1)) == 0) - goto out; + blocksize = 1 << inode->i_blkbits; + length = offset & (blocksize - 1); + + /* Block boundary? Nothing to do */ + if (!length) + return 0; + + length = blocksize - length; + iblock = (sector_t)index << (PAGE_CACHE_SHIFT - inode->i_blkbits); - ret = -ENOMEM; page = grab_cache_page(mapping, index); + err = -ENOMEM; if (!page) goto out; - to = (offset + blocksize) & ~(blocksize - 1); - ret = a_ops->prepare_write(NULL, page, offset, to); - if (ret == 0) { - kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); - set_page_dirty(page); + if (page_has_buffers(page)) { +has_buffers: + unlock_page(page); + page_cache_release(page); + return block_truncate_page(mapping, from, get_block); + } + + /* Find the buffer that contains "offset" */ + pos = blocksize; + while (offset >= pos) { + iblock++; + pos += blocksize; + } + + map_bh.b_size = blocksize; + map_bh.b_state = 0; + err = get_block(inode, iblock, &map_bh, 0); + if (err) + goto unlock; + /* unmapped? It's a hole - nothing to do */ + if (!buffer_mapped(&map_bh)) + goto unlock; + + /* Ok, it's mapped. Make sure it's up-to-date */ + if (!PageUptodate(page)) { + err = mapping->a_ops->readpage(NULL, page); + if (err) { + page_cache_release(page); + goto out; + } + lock_page(page); + if (!PageUptodate(page)) { + err = -EIO; + goto unlock; + } + if (page_has_buffers(page)) + goto has_buffers; } + zero_user(page, offset, length); + set_page_dirty(page); + err = 0; + +unlock: unlock_page(page); page_cache_release(page); out: - return ret; + return err; } EXPORT_SYMBOL(nobh_truncate_page); @@ -2599,12 +2819,11 @@ int block_truncate_page(struct address_space *mapping, pgoff_t index = from >> PAGE_CACHE_SHIFT; unsigned offset = from & (PAGE_CACHE_SIZE-1); unsigned blocksize; - pgoff_t iblock; + sector_t iblock; unsigned length, pos; struct inode *inode = mapping->host; struct page *page; struct buffer_head *bh; - void *kaddr; int err; blocksize = 1 << inode->i_blkbits; @@ -2615,7 +2834,7 @@ int block_truncate_page(struct address_space *mapping, return 0; length = blocksize - length; - iblock = index << (PAGE_CACHE_SHIFT - inode->i_blkbits); + iblock = (sector_t)index << (PAGE_CACHE_SHIFT - inode->i_blkbits); page = grab_cache_page(mapping, index); err = -ENOMEM; @@ -2636,6 +2855,7 @@ int block_truncate_page(struct address_space *mapping, err = 0; if (!buffer_mapped(bh)) { + WARN_ON(bh->b_size != blocksize); err = get_block(inode, iblock, bh, 0); if (err) goto unlock; @@ -2648,7 +2868,7 @@ int block_truncate_page(struct address_space *mapping, if (PageUptodate(page)) set_buffer_uptodate(bh); - if (!buffer_uptodate(bh) && !buffer_delay(bh)) { + if (!buffer_uptodate(bh) && !buffer_delay(bh) && !buffer_unwritten(bh)) { err = -EIO; ll_rw_block(READ, 1, &bh); wait_on_buffer(bh); @@ -2657,11 +2877,7 @@ int block_truncate_page(struct address_space *mapping, goto unlock; } - kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr + offset, 0, length); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); - + zero_user(page, offset, length); mark_buffer_dirty(bh); err = 0; @@ -2671,6 +2887,7 @@ unlock: out: return err; } +EXPORT_SYMBOL(block_truncate_page); /* * The generic ->writepage function for buffer-backed address_spaces @@ -2682,11 +2899,11 @@ int block_write_full_page(struct page *page, get_block_t *get_block, loff_t i_size = i_size_read(inode); const pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT; unsigned offset; - void *kaddr; /* Is the page fully inside i_size? */ if (page->index < end_index) - return __block_write_full_page(inode, page, get_block, wbc); + return __block_write_full_page(inode, page, get_block, wbc, + end_buffer_async_write); /* Is the page fully outside i_size? (truncate in progress) */ offset = i_size & (PAGE_CACHE_SIZE-1); @@ -2696,24 +2913,23 @@ int block_write_full_page(struct page *page, get_block_t *get_block, * they may have been added in ext3_writepage(). Make them * freeable here, so the page does not leak. */ - block_invalidatepage(page, 0); + do_invalidatepage(page, 0, PAGE_CACHE_SIZE); unlock_page(page); return 0; /* don't care */ } /* * The page straddles i_size. It must be zeroed out on each and every - * writepage invokation because it may be mmapped. "A file is mapped + * writepage invocation because it may be mmapped. "A file is mapped * in multiples of the page size. For a file that is not a multiple of * the page size, the remaining memory is zeroed when mapped, and * writes to that region are not written out to the file." */ - kaddr = kmap_atomic(page, KM_USER0); - memset(kaddr + offset, 0, PAGE_CACHE_SIZE - offset); - flush_dcache_page(page); - kunmap_atomic(kaddr, KM_USER0); - return __block_write_full_page(inode, page, get_block, wbc); + zero_user_segment(page, offset, PAGE_CACHE_SIZE); + return __block_write_full_page(inode, page, get_block, wbc, + end_buffer_async_write); } +EXPORT_SYMBOL(block_write_full_page); sector_t generic_block_bmap(struct address_space *mapping, sector_t block, get_block_t *get_block) @@ -2722,28 +2938,78 @@ sector_t generic_block_bmap(struct address_space *mapping, sector_t block, struct inode *inode = mapping->host; tmp.b_state = 0; tmp.b_blocknr = 0; + tmp.b_size = 1 << inode->i_blkbits; get_block(inode, block, &tmp, 0); return tmp.b_blocknr; } +EXPORT_SYMBOL(generic_block_bmap); -static int end_bio_bh_io_sync(struct bio *bio, unsigned int bytes_done, int err) +static void end_bio_bh_io_sync(struct bio *bio, int err) { struct buffer_head *bh = bio->bi_private; - if (bio->bi_size) - return 1; - if (err == -EOPNOTSUPP) { set_bit(BIO_EOPNOTSUPP, &bio->bi_flags); - set_bit(BH_Eopnotsupp, &bh->b_state); } + if (unlikely (test_bit(BIO_QUIET,&bio->bi_flags))) + set_bit(BH_Quiet, &bh->b_state); + bh->b_end_io(bh, test_bit(BIO_UPTODATE, &bio->bi_flags)); bio_put(bio); - return 0; } -int submit_bh(int rw, struct buffer_head * bh) +/* + * This allows us to do IO even on the odd last sectors + * of a device, even if the bh block size is some multiple + * of the physical sector size. + * + * We'll just truncate the bio to the size of the device, + * and clear the end of the buffer head manually. + * + * Truly out-of-range accesses will turn into actual IO + * errors, this only handles the "we need to be able to + * do IO at the final sector" case. + */ +static void guard_bh_eod(int rw, struct bio *bio, struct buffer_head *bh) +{ + sector_t maxsector; + unsigned bytes; + + maxsector = i_size_read(bio->bi_bdev->bd_inode) >> 9; + if (!maxsector) + return; + + /* + * If the *whole* IO is past the end of the device, + * let it through, and the IO layer will turn it into + * an EIO. + */ + if (unlikely(bio->bi_iter.bi_sector >= maxsector)) + return; + + maxsector -= bio->bi_iter.bi_sector; + bytes = bio->bi_iter.bi_size; + if (likely((bytes >> 9) <= maxsector)) + return; + + /* Uhhuh. We've got a bh that straddles the device size! */ + bytes = maxsector << 9; + + /* Truncate the bio.. */ + bio->bi_iter.bi_size = bytes; + bio->bi_io_vec[0].bv_len = bytes; + + /* ..and clear the end of the buffer for reads */ + if ((rw & RW_MASK) == READ) { + void *kaddr = kmap_atomic(bh->b_page); + memset(kaddr + bh_offset(bh) + bytes, 0, bh->b_size - bytes); + kunmap_atomic(kaddr); + flush_dcache_page(bh->b_page); + } +} + +int _submit_bh(int rw, struct buffer_head *bh, unsigned long bio_flags) { struct bio *bio; int ret = 0; @@ -2751,15 +3017,13 @@ int submit_bh(int rw, struct buffer_head * bh) BUG_ON(!buffer_locked(bh)); BUG_ON(!buffer_mapped(bh)); BUG_ON(!bh->b_end_io); - - if (buffer_ordered(bh) && (rw == WRITE)) - rw = WRITE_BARRIER; + BUG_ON(buffer_delay(bh)); + BUG_ON(buffer_unwritten(bh)); /* - * Only clear out a write error when rewriting, should this - * include WRITE_SYNC as well? + * Only clear out a write error when rewriting */ - if (test_set_buffer_req(bh) && (rw == WRITE || rw == WRITE_BARRIER)) + if (test_set_buffer_req(bh) && (rw & WRITE)) clear_buffer_write_io_error(bh); /* @@ -2768,18 +3032,26 @@ int submit_bh(int rw, struct buffer_head * bh) */ bio = bio_alloc(GFP_NOIO, 1); - bio->bi_sector = bh->b_blocknr * (bh->b_size >> 9); + bio->bi_iter.bi_sector = bh->b_blocknr * (bh->b_size >> 9); bio->bi_bdev = bh->b_bdev; bio->bi_io_vec[0].bv_page = bh->b_page; bio->bi_io_vec[0].bv_len = bh->b_size; bio->bi_io_vec[0].bv_offset = bh_offset(bh); bio->bi_vcnt = 1; - bio->bi_idx = 0; - bio->bi_size = bh->b_size; + bio->bi_iter.bi_size = bh->b_size; bio->bi_end_io = end_bio_bh_io_sync; bio->bi_private = bh; + bio->bi_flags |= bio_flags; + + /* Take care of bh's that straddle the end of the device */ + guard_bh_eod(rw, bio, bh); + + if (buffer_meta(bh)) + rw |= REQ_META; + if (buffer_prio(bh)) + rw |= REQ_PRIO; bio_get(bio); submit_bio(rw, bio); @@ -2790,28 +3062,34 @@ int submit_bh(int rw, struct buffer_head * bh) bio_put(bio); return ret; } +EXPORT_SYMBOL_GPL(_submit_bh); + +int submit_bh(int rw, struct buffer_head *bh) +{ + return _submit_bh(rw, bh, 0); +} +EXPORT_SYMBOL(submit_bh); /** * ll_rw_block: low-level access to block devices (DEPRECATED) - * @rw: whether to %READ or %WRITE or %SWRITE or maybe %READA (readahead) + * @rw: whether to %READ or %WRITE or maybe %READA (readahead) * @nr: number of &struct buffer_heads in the array * @bhs: array of pointers to &struct buffer_head * * ll_rw_block() takes an array of pointers to &struct buffer_heads, and * requests an I/O operation on them, either a %READ or a %WRITE. The third - * %SWRITE is like %WRITE only we make sure that the *current* data in buffers - * are sent to disk. The fourth %READA option is described in the documentation - * for generic_make_request() which ll_rw_block() calls. + * %READA option is described in the documentation for generic_make_request() + * which ll_rw_block() calls. * * This function drops any buffer that it cannot get a lock on (with the - * BH_Lock state bit) unless SWRITE is required, any buffer that appears to be - * clean when doing a write request, and any buffer that appears to be - * up-to-date when doing read request. Further it marks as clean buffers that - * are processed for writing (the buffer cache won't assume that they are - * actually clean until the buffer gets unlocked). + * BH_Lock state bit), any buffer that appears to be clean when doing a write + * request, and any buffer that appears to be up-to-date when doing read + * request. Further it marks as clean buffers that are processed for + * writing (the buffer cache won't assume that they are actually clean + * until the buffer gets unlocked). * * ll_rw_block sets b_end_io to simple completion handler that marks - * the buffer up-to-date (if approriate), unlocks the buffer and wakes + * the buffer up-to-date (if appropriate), unlocks the buffer and wakes * any waiters. * * All of the buffers must be for the same device, and must also be a @@ -2824,36 +3102,47 @@ void ll_rw_block(int rw, int nr, struct buffer_head *bhs[]) for (i = 0; i < nr; i++) { struct buffer_head *bh = bhs[i]; - if (rw == SWRITE) - lock_buffer(bh); - else if (test_set_buffer_locked(bh)) + if (!trylock_buffer(bh)) continue; - - get_bh(bh); - if (rw == WRITE || rw == SWRITE) { + if (rw == WRITE) { if (test_clear_buffer_dirty(bh)) { bh->b_end_io = end_buffer_write_sync; + get_bh(bh); submit_bh(WRITE, bh); continue; } } else { if (!buffer_uptodate(bh)) { bh->b_end_io = end_buffer_read_sync; + get_bh(bh); submit_bh(rw, bh); continue; } } unlock_buffer(bh); - put_bh(bh); } } +EXPORT_SYMBOL(ll_rw_block); + +void write_dirty_buffer(struct buffer_head *bh, int rw) +{ + lock_buffer(bh); + if (!test_clear_buffer_dirty(bh)) { + unlock_buffer(bh); + return; + } + bh->b_end_io = end_buffer_write_sync; + get_bh(bh); + submit_bh(rw, bh); +} +EXPORT_SYMBOL(write_dirty_buffer); /* * For a data-integrity writeout, we need to wait upon any in-progress I/O * and then start new I/O and then wait upon it. The caller must have a ref on * the buffer_head. */ -int sync_dirty_buffer(struct buffer_head *bh) +int __sync_dirty_buffer(struct buffer_head *bh, int rw) { int ret = 0; @@ -2862,12 +3151,8 @@ int sync_dirty_buffer(struct buffer_head *bh) if (test_clear_buffer_dirty(bh)) { get_bh(bh); bh->b_end_io = end_buffer_write_sync; - ret = submit_bh(WRITE, bh); + ret = submit_bh(rw, bh); wait_on_buffer(bh); - if (buffer_eopnotsupp(bh)) { - clear_buffer_eopnotsupp(bh); - ret = -EOPNOTSUPP; - } if (!ret && !buffer_uptodate(bh)) ret = -EIO; } else { @@ -2875,6 +3160,13 @@ int sync_dirty_buffer(struct buffer_head *bh) } return ret; } +EXPORT_SYMBOL(__sync_dirty_buffer); + +int sync_dirty_buffer(struct buffer_head *bh) +{ + return __sync_dirty_buffer(bh, WRITE_SYNC); +} +EXPORT_SYMBOL(sync_dirty_buffer); /* * try_to_free_buffers() checks if all the buffers on this particular page @@ -2920,7 +3212,7 @@ drop_buffers(struct page *page, struct buffer_head **buffers_to_free) do { struct buffer_head *next = bh->b_this_page; - if (!list_empty(&bh->b_assoc_buffers)) + if (bh->b_assoc_map) __remove_assoc_queue(bh); bh = next; } while (bh != head); @@ -2948,17 +3240,23 @@ int try_to_free_buffers(struct page *page) spin_lock(&mapping->private_lock); ret = drop_buffers(page, &buffers_to_free); - if (ret) { - /* - * If the filesystem writes its buffers by hand (eg ext3) - * then we can have clean buffers against a dirty page. We - * clean the page here; otherwise later reattachment of buffers - * could encounter a non-uptodate page, which is unresolvable. - * This only applies in the rare case where try_to_free_buffers - * succeeds but the page is not freed. - */ - clear_page_dirty(page); - } + + /* + * If the filesystem writes its buffers by hand (eg ext3) + * then we can have clean buffers against a dirty page. We + * clean the page here; otherwise the VM will never notice + * that the filesystem did any IO at all. + * + * Also, during truncate, discard_buffer will have marked all + * the page's buffers clean. We discover that here and clean + * the page also. + * + * private_lock must be held over this entire operation in order + * to synchronise against __set_page_dirty_buffers and prevent the + * dirty bit from being lost. + */ + if (ret) + cancel_dirty_page(page, PAGE_CACHE_SIZE); spin_unlock(&mapping->private_lock); out: if (buffers_to_free) { @@ -2974,25 +3272,14 @@ out: } EXPORT_SYMBOL(try_to_free_buffers); -int block_sync_page(struct page *page) -{ - struct address_space *mapping; - - smp_mb(); - mapping = page_mapping(page); - if (mapping) - blk_run_backing_dev(mapping->backing_dev_info, page); - return 0; -} - /* * There are no bdflush tunables left. But distributions are * still running obsolete flush daemons, so we terminate them here. * * Use of bdflush() is deprecated and will be removed in a future kernel. - * The `pdflush' kernel threads fully replace bdflush daemons and this call. + * The `flush-X' kernel threads fully replace bdflush daemons and this call. */ -asmlinkage long sys_bdflush(int func, long data) +SYSCALL_DEFINE2(bdflush, int, func, long, data) { static int msg_count; @@ -3015,13 +3302,13 @@ asmlinkage long sys_bdflush(int func, long data) /* * Buffer-head allocation */ -static kmem_cache_t *bh_cachep; +static struct kmem_cache *bh_cachep __read_mostly; /* * Once the number of bh's in the machine exceeds this level, we start * stripping them in writeback. */ -static int max_buffer_heads; +static unsigned long max_buffer_heads; int buffer_heads_over_limit; @@ -3037,21 +3324,23 @@ static void recalc_bh_state(void) int i; int tot = 0; - if (__get_cpu_var(bh_accounting).ratelimit++ < 4096) + if (__this_cpu_inc_return(bh_accounting.ratelimit) - 1 < 4096) return; - __get_cpu_var(bh_accounting).ratelimit = 0; - for_each_cpu(i) + __this_cpu_write(bh_accounting.ratelimit, 0); + for_each_online_cpu(i) tot += per_cpu(bh_accounting, i).nr; buffer_heads_over_limit = (tot > max_buffer_heads); } - + struct buffer_head *alloc_buffer_head(gfp_t gfp_flags) { - struct buffer_head *ret = kmem_cache_alloc(bh_cachep, gfp_flags); + struct buffer_head *ret = kmem_cache_zalloc(bh_cachep, gfp_flags); if (ret) { - get_cpu_var(bh_accounting).nr++; + INIT_LIST_HEAD(&ret->b_assoc_buffers); + preempt_disable(); + __this_cpu_inc(bh_accounting.nr); recalc_bh_state(); - put_cpu_var(bh_accounting); + preempt_enable(); } return ret; } @@ -3061,25 +3350,13 @@ void free_buffer_head(struct buffer_head *bh) { BUG_ON(!list_empty(&bh->b_assoc_buffers)); kmem_cache_free(bh_cachep, bh); - get_cpu_var(bh_accounting).nr--; + preempt_disable(); + __this_cpu_dec(bh_accounting.nr); recalc_bh_state(); - put_cpu_var(bh_accounting); + preempt_enable(); } EXPORT_SYMBOL(free_buffer_head); -static void -init_buffer_head(void *data, kmem_cache_t *cachep, unsigned long flags) -{ - if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == - SLAB_CTOR_CONSTRUCTOR) { - struct buffer_head * bh = (struct buffer_head *)data; - - memset(bh, 0, sizeof(*bh)); - INIT_LIST_HEAD(&bh->b_assoc_buffers); - } -} - -#ifdef CONFIG_HOTPLUG_CPU static void buffer_exit_cpu(int cpu) { int i; @@ -3089,24 +3366,71 @@ static void buffer_exit_cpu(int cpu) brelse(b->bhs[i]); b->bhs[i] = NULL; } + this_cpu_add(bh_accounting.nr, per_cpu(bh_accounting, cpu).nr); + per_cpu(bh_accounting, cpu).nr = 0; } static int buffer_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) { - if (action == CPU_DEAD) + if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) buffer_exit_cpu((unsigned long)hcpu); return NOTIFY_OK; } -#endif /* CONFIG_HOTPLUG_CPU */ + +/** + * bh_uptodate_or_lock - Test whether the buffer is uptodate + * @bh: struct buffer_head + * + * Return true if the buffer is up-to-date and false, + * with the buffer locked, if not. + */ +int bh_uptodate_or_lock(struct buffer_head *bh) +{ + if (!buffer_uptodate(bh)) { + lock_buffer(bh); + if (!buffer_uptodate(bh)) + return 0; + unlock_buffer(bh); + } + return 1; +} +EXPORT_SYMBOL(bh_uptodate_or_lock); + +/** + * bh_submit_read - Submit a locked buffer for reading + * @bh: struct buffer_head + * + * Returns zero on success and -EIO on error. + */ +int bh_submit_read(struct buffer_head *bh) +{ + BUG_ON(!buffer_locked(bh)); + + if (buffer_uptodate(bh)) { + unlock_buffer(bh); + return 0; + } + + get_bh(bh); + bh->b_end_io = end_buffer_read_sync; + submit_bh(READ, bh); + wait_on_buffer(bh); + if (buffer_uptodate(bh)) + return 0; + return -EIO; +} +EXPORT_SYMBOL(bh_submit_read); void __init buffer_init(void) { - int nrpages; + unsigned long nrpages; bh_cachep = kmem_cache_create("buffer_head", sizeof(struct buffer_head), 0, - SLAB_RECLAIM_ACCOUNT|SLAB_PANIC, init_buffer_head, NULL); + (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| + SLAB_MEM_SPREAD), + NULL); /* * Limit the bh occupancy to 10% of ZONE_NORMAL @@ -3115,29 +3439,3 @@ void __init buffer_init(void) max_buffer_heads = nrpages * (PAGE_SIZE / sizeof(struct buffer_head)); hotcpu_notifier(buffer_cpu_notify, 0); } - -EXPORT_SYMBOL(__bforget); -EXPORT_SYMBOL(__brelse); -EXPORT_SYMBOL(__wait_on_buffer); -EXPORT_SYMBOL(block_commit_write); -EXPORT_SYMBOL(block_prepare_write); -EXPORT_SYMBOL(block_read_full_page); -EXPORT_SYMBOL(block_sync_page); -EXPORT_SYMBOL(block_truncate_page); -EXPORT_SYMBOL(block_write_full_page); -EXPORT_SYMBOL(cont_prepare_write); -EXPORT_SYMBOL(end_buffer_async_write); -EXPORT_SYMBOL(end_buffer_read_sync); -EXPORT_SYMBOL(end_buffer_write_sync); -EXPORT_SYMBOL(file_fsync); -EXPORT_SYMBOL(fsync_bdev); -EXPORT_SYMBOL(generic_block_bmap); -EXPORT_SYMBOL(generic_commit_write); -EXPORT_SYMBOL(generic_cont_expand); -EXPORT_SYMBOL(init_buffer); -EXPORT_SYMBOL(invalidate_bdev); -EXPORT_SYMBOL(ll_rw_block); -EXPORT_SYMBOL(mark_buffer_dirty); -EXPORT_SYMBOL(submit_bh); -EXPORT_SYMBOL(sync_dirty_buffer); -EXPORT_SYMBOL(unlock_buffer); |