xfs: prevent deadlock in xfs_qm_shake()
[safe/jmp/linux-2.6] / fs / buffer.c
index 109b261..f5f8b15 100644 (file)
@@ -76,8 +76,7 @@ EXPORT_SYMBOL(__lock_buffer);
 
 void unlock_buffer(struct buffer_head *bh)
 {
-       smp_mb__before_clear_bit();
-       clear_buffer_locked(bh);
+       clear_bit_unlock(BH_Lock, &bh->b_state);
        smp_mb__after_clear_bit();
        wake_up_bit(&bh->b_state, BH_Lock);
 }
@@ -100,10 +99,18 @@ __clear_page_buffers(struct page *page)
        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);
@@ -145,7 +152,7 @@ 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 (!buffer_eopnotsupp(bh) && !quiet_error(bh)) {
                        buffer_io_error(bh);
                        printk(KERN_WARNING "lost page write due to "
                                        "I/O error on %s\n",
@@ -159,95 +166,6 @@ void end_buffer_write_sync(struct buffer_head *bh, int uptodate)
 }
 
 /*
- * 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)
-               ret = filemap_write_and_wait(bdev->bd_inode->i_mapping);
-       return ret;
-}
-EXPORT_SYMBOL(sync_blockdev);
-
-/*
- * 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();
-
-               __fsync_super(sb);
-
-               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);
-
-/*
  * Various filesystems appear to want __find_get_block to be non-blocking.
  * But it's the page lock which protects the buffers.  To get around this,
  * we get exclusion from try_to_free_buffers with the blockdev mapping's
@@ -372,7 +290,7 @@ static void free_more_memory(void)
                                                &zone);
                if (zone)
                        try_to_free_pages(node_zonelist(nid, GFP_NOFS), 0,
-                                               GFP_NOFS);
+                                               GFP_NOFS, NULL);
        }
 }
 
@@ -395,7 +313,7 @@ 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);
        }
@@ -456,7 +374,7 @@ static 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",
@@ -580,7 +498,7 @@ 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);
@@ -629,6 +547,39 @@ repeat:
        return err;
 }
 
+void do_thaw_all(unsigned long unused)
+{
+       struct super_block *sb;
+       char b[BDEVNAME_SIZE];
+
+       spin_lock(&sb_lock);
+restart:
+       list_for_each_entry(sb, &super_blocks, s_list) {
+               sb->s_count++;
+               spin_unlock(&sb_lock);
+               down_read(&sb->s_umount);
+               while (sb->s_bdev && !thaw_bdev(sb->s_bdev, sb))
+                       printk(KERN_WARNING "Emergency Thaw on %s\n",
+                              bdevname(sb->s_bdev, b));
+               up_read(&sb->s_umount);
+               spin_lock(&sb_lock);
+               if (__put_super_and_need_restart(sb))
+                       goto restart;
+       }
+       spin_unlock(&sb_lock);
+       printk(KERN_WARNING "Emergency Thaw complete\n");
+}
+
+/**
+ * emergency_thaw_all -- forcibly thaw every frozen filesystem
+ *
+ * Used for emergency unfreeze of all filesystems via SysRq
+ */
+void emergency_thaw_all(void)
+{
+       pdflush_operation(do_thaw_all, 0);
+}
+
 /**
  * sync_mapping_buffers - write out & wait upon a mapping's "associated" buffers
  * @mapping: the mapping which wants those buffers written
@@ -697,32 +648,18 @@ EXPORT_SYMBOL(mark_buffer_dirty_inode);
  * If warn is true, then emit a warning if the page is not uptodate and has
  * not been truncated.
  */
-static int __set_page_dirty(struct page *page,
+static void __set_page_dirty(struct page *page,
                struct address_space *mapping, int warn)
 {
-       if (unlikely(!mapping))
-               return !TestSetPageDirty(page);
-
-       if (TestSetPageDirty(page))
-               return 0;
-
        spin_lock_irq(&mapping->tree_lock);
        if (page->mapping) {    /* Race with truncate? */
                WARN_ON_ONCE(warn && !PageUptodate(page));
-
-               if (mapping_cap_account_dirty(mapping)) {
-                       __inc_zone_page_state(page, NR_FILE_DIRTY);
-                       __inc_bdi_stat(mapping->backing_dev_info,
-                                       BDI_RECLAIMABLE);
-                       task_io_account_write(PAGE_CACHE_SIZE);
-               }
+               account_page_dirtied(page, mapping);
                radix_tree_tag_set(&mapping->page_tree,
                                page_index(page), PAGECACHE_TAG_DIRTY);
        }
        spin_unlock_irq(&mapping->tree_lock);
        __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
-
-       return 1;
 }
 
 /*
@@ -752,6 +689,7 @@ static int __set_page_dirty(struct page *page,
  */
 int __set_page_dirty_buffers(struct page *page)
 {
+       int newly_dirty;
        struct address_space *mapping = page_mapping(page);
 
        if (unlikely(!mapping))
@@ -767,9 +705,12 @@ 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);
 
-       return __set_page_dirty(page, mapping, 1);
+       if (newly_dirty)
+               __set_page_dirty(page, mapping, 1);
+       return newly_dirty;
 }
 EXPORT_SYMBOL(__set_page_dirty_buffers);
 
@@ -879,6 +820,7 @@ 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
@@ -1197,8 +1139,11 @@ void mark_buffer_dirty(struct buffer_head *bh)
                        return;
        }
 
-       if (!test_set_buffer_dirty(bh))
-               __set_page_dirty(bh->b_page, page_mapping(bh->b_page), 0);
+       if (!test_set_buffer_dirty(bh)) {
+               struct page *page = bh->b_page;
+               if (!TestSetPageDirty(page))
+                       __set_page_dirty(page, page_mapping(page), 0);
+       }
 }
 
 /*
@@ -1214,8 +1159,7 @@ 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");
 }
 
 /*
@@ -1721,7 +1665,7 @@ static int __block_write_full_page(struct inode *inode, struct page *page,
                 */
                if (wbc->sync_mode != WB_SYNC_NONE || !wbc->nonblocking) {
                        lock_buffer(bh);
-               } else if (test_set_buffer_locked(bh)) {
+               } else if (!trylock_buffer(bh)) {
                        redirty_page_for_writepage(wbc, page);
                        continue;
                }
@@ -1989,7 +1933,7 @@ int block_write_begin(struct file *file, struct address_space *mapping,
        page = *pagep;
        if (page == NULL) {
                ownpage = 1;
-               page = __grab_cache_page(mapping, index);
+               page = grab_cache_page_write_begin(mapping, index, flags);
                if (!page) {
                        status = -ENOMEM;
                        goto out;
@@ -2015,7 +1959,6 @@ int block_write_begin(struct file *file, struct address_space *mapping,
                        if (pos + len > inode->i_size)
                                vmtruncate(inode, inode->i_size);
                }
-               goto out;
        }
 
 out:
@@ -2097,6 +2040,52 @@ int generic_write_end(struct file *file, struct address_space *mapping,
 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, read_descriptor_t *desc,
+                                       unsigned long from)
+{
+       struct inode *inode = page->mapping->host;
+       unsigned block_start, block_end, blocksize;
+       unsigned to;
+       struct buffer_head *bh, *head;
+       int ret = 1;
+
+       if (!page_has_buffers(page))
+               return 0;
+
+       blocksize = 1 << inode->i_blkbits;
+       to = min_t(unsigned, PAGE_CACHE_SIZE - from, desc->count);
+       to = from + to;
+       if (from < blocksize && to > PAGE_CACHE_SIZE - blocksize)
+               return 0;
+
+       head = page_buffers(page);
+       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
@@ -2357,13 +2346,14 @@ int block_commit_write(struct page *page, unsigned from, unsigned to)
  * unlock the page.
  */
 int
-block_page_mkwrite(struct vm_area_struct *vma, struct page *page,
+block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
                   get_block_t get_block)
 {
+       struct page *page = vmf->page;
        struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
        unsigned long end;
        loff_t size;
-       int ret = -EINVAL;
+       int ret = VM_FAULT_NOPAGE; /* make the VM retry the fault */
 
        lock_page(page);
        size = i_size_read(inode);
@@ -2383,6 +2373,13 @@ block_page_mkwrite(struct vm_area_struct *vma, struct page *page,
        if (!ret)
                ret = block_commit_write(page, 0, end);
 
+       if (unlikely(ret)) {
+               if (ret == -ENOMEM)
+                       ret = VM_FAULT_OOM;
+               else /* -ENOSPC, -EIO, etc */
+                       ret = VM_FAULT_SIGBUS;
+       }
+
 out_unlock:
        unlock_page(page);
        return ret;
@@ -2449,7 +2446,7 @@ int nobh_write_begin(struct file *file, struct address_space *mapping,
        from = pos & (PAGE_CACHE_SIZE - 1);
        to = from + len;
 
-       page = __grab_cache_page(mapping, index);
+       page = grab_cache_page_write_begin(mapping, index, flags);
        if (!page)
                return -ENOMEM;
        *pagep = page;
@@ -2580,7 +2577,7 @@ int nobh_write_end(struct file *file, struct address_space *mapping,
        struct buffer_head *bh;
        BUG_ON(fsdata != NULL && page_has_buffers(page));
 
-       if (unlikely(copied < len) && !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,
@@ -2868,6 +2865,9 @@ static void end_bio_bh_io_sync(struct bio *bio, int err)
                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);
 }
@@ -2881,14 +2881,17 @@ int submit_bh(int rw, struct buffer_head * bh)
        BUG_ON(!buffer_mapped(bh));
        BUG_ON(!bh->b_end_io);
 
-       if (buffer_ordered(bh) && (rw == WRITE))
-               rw = WRITE_BARRIER;
+       /*
+        * Mask in barrier bit for a write (could be either a WRITE or a
+        * WRITE_SYNC
+        */
+       if (buffer_ordered(bh) && (rw & WRITE))
+               rw |= WRITE_BARRIER;
 
        /*
-        * 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);
 
        /*
@@ -2955,7 +2958,7 @@ void ll_rw_block(int rw, int nr, struct buffer_head *bhs[])
 
                if (rw == SWRITE || rw == SWRITE_SYNC)
                        lock_buffer(bh);
-               else if (test_set_buffer_locked(bh))
+               else if (!trylock_buffer(bh))
                        continue;
 
                if (rw == WRITE || rw == SWRITE || rw == SWRITE_SYNC) {
@@ -2994,7 +2997,7 @@ 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_SYNC, bh);
+               ret = submit_bh(WRITE, bh);
                wait_on_buffer(bh);
                if (buffer_eopnotsupp(bh)) {
                        clear_buffer_eopnotsupp(bh);
@@ -3129,7 +3132,7 @@ void block_sync_page(struct page *page)
  * Use of bdflush() is deprecated and will be removed in a future kernel.
  * The `pdflush' 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;
 
@@ -3272,7 +3275,7 @@ int bh_submit_read(struct buffer_head *bh)
 EXPORT_SYMBOL(bh_submit_read);
 
 static void
-init_buffer_head(struct kmem_cache *cachep, void *data)
+init_buffer_head(void *data)
 {
        struct buffer_head *bh = data;