1 files changed, 34 insertions, 36 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 4b833972273a..f19e1259a971 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -112,8 +112,6 @@ static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
         int err = 0;
         int i;
         struct inode *inode = fdentry(file)->d_inode;
-        struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
-        u64 hint_byte;
         u64 num_bytes;
         u64 start_pos;
         u64 end_of_last_block;
@@ -125,23 +123,10 @@ static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
                     root->sectorsize - 1) & ~((u64)root->sectorsize - 1);
 
         end_of_last_block = start_pos + num_bytes - 1;
+        err = btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block);
+        if (err)
+                return err;
 
-        lock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
-        trans = btrfs_join_transaction(root, 1);
-        if (!trans) {
-                err = -ENOMEM;
-                goto out_unlock;
-        }
-        btrfs_set_trans_block_group(trans, inode);
-        hint_byte = 0;
-
-        set_extent_uptodate(io_tree, start_pos, end_of_last_block, GFP_NOFS);
-
-        /* check for reserved extents on each page, we don't want
-         * to reset the delalloc bit on things that already have
-         * extents reserved.
-         */
-        btrfs_set_extent_delalloc(inode, start_pos, end_of_last_block);
         for (i = 0; i < num_pages; i++) {
                 struct page *p = pages[i];
                 SetPageUptodate(p);
@@ -155,9 +140,6 @@ static noinline int dirty_and_release_pages(struct btrfs_trans_handle *trans,
                  * at this time.
                  */
         }
-        err = btrfs_end_transaction(trans, root);
-out_unlock:
-        unlock_extent(io_tree, start_pos, end_of_last_block, GFP_NOFS);
         return err;
 }
 
@@ -189,18 +171,18 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
                 if (!split2)
                         split2 = alloc_extent_map(GFP_NOFS);
 
-                spin_lock(&em_tree->lock);
+                write_lock(&em_tree->lock);
                 em = lookup_extent_mapping(em_tree, start, len);
                 if (!em) {
-                        spin_unlock(&em_tree->lock);
+                        write_unlock(&em_tree->lock);
                         break;
                 }
                 flags = em->flags;
                 if (skip_pinned && test_bit(EXTENT_FLAG_PINNED, &em->flags)) {
-                        spin_unlock(&em_tree->lock);
                         if (em->start <= start &&
                             (!testend || em->start + em->len >= start + len)) {
                                 free_extent_map(em);
+                                write_unlock(&em_tree->lock);
                                 break;
                         }
                         if (start < em->start) {
@@ -210,6 +192,7 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
                                 start = em->start + em->len;
                         }
                         free_extent_map(em);
+                        write_unlock(&em_tree->lock);
                         continue;
                 }
                 compressed = test_bit(EXTENT_FLAG_COMPRESSED, &em->flags);
@@ -260,7 +243,7 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
                         free_extent_map(split);
                         split = NULL;
                 }
-                spin_unlock(&em_tree->lock);
+                write_unlock(&em_tree->lock);
 
                 /* once for us */
                 free_extent_map(em);
@@ -289,7 +272,7 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
 noinline int btrfs_drop_extents(struct btrfs_trans_handle *trans,
                        struct btrfs_root *root, struct inode *inode,
                        u64 start, u64 end, u64 locked_end,
-                       u64 inline_limit, u64 *hint_byte)
+                       u64 inline_limit, u64 *hint_byte, int drop_cache)
 {
         u64 extent_end = 0;
         u64 search_start = start;
@@ -314,7 +297,8 @@ noinline int btrfs_drop_extents(struct btrfs_trans_handle *trans,
         int ret;
 
         inline_limit = 0;
-        btrfs_drop_extent_cache(inode, start, end - 1, 0);
+        if (drop_cache)
+                btrfs_drop_extent_cache(inode, start, end - 1, 0);
 
         path = btrfs_alloc_path();
         if (!path)
@@ -936,21 +920,35 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
         start_pos = pos;
 
         vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);
+
+        /* do the reserve before the mutex lock in case we have to do some
+         * flushing.  We wouldn't deadlock, but this is more polite.
+         */
+        err = btrfs_reserve_metadata_for_delalloc(root, inode, 1);
+        if (err)
+                goto out_nolock;
+
+        mutex_lock(&inode->i_mutex);
+
         current->backing_dev_info = inode->i_mapping->backing_dev_info;
         err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
         if (err)
-                goto out_nolock;
+                goto out;
+
         if (count == 0)
-                goto out_nolock;
+                goto out;
 
         err = file_remove_suid(file);
         if (err)
-                goto out_nolock;
+                goto out;
+
         file_update_time(file);
 
         pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL);
 
-        mutex_lock(&inode->i_mutex);
+        /* generic_write_checks can change our pos */
+        start_pos = pos;
+
         BTRFS_I(inode)->sequence++;
         first_index = pos >> PAGE_CACHE_SHIFT;
         last_index = (pos + count) >> PAGE_CACHE_SHIFT;
@@ -1024,9 +1022,8 @@ static ssize_t btrfs_file_write(struct file *file, const char __user *buf,
                 }
 
                 if (will_write) {
-                        btrfs_fdatawrite_range(inode->i_mapping, pos,
-                                               pos + write_bytes - 1,
-                                               WB_SYNC_ALL);
+                        filemap_fdatawrite_range(inode->i_mapping, pos,
+                                                 pos + write_bytes - 1);
                 } else {
                         balance_dirty_pages_ratelimited_nr(inode->i_mapping,
                                                            num_pages);
@@ -1047,6 +1044,7 @@ out:
         mutex_unlock(&inode->i_mutex);
         if (ret)
                 err = ret;
+        btrfs_unreserve_metadata_for_delalloc(root, inode, 1);
 
 out_nolock:
         kfree(pages);
@@ -1203,7 +1201,7 @@ out:
         return ret > 0 ? EIO : ret;
 }
 
-static struct vm_operations_struct btrfs_file_vm_ops = {
+static const struct vm_operations_struct btrfs_file_vm_ops = {
         .fault          = filemap_fault,
         .page_mkwrite   = btrfs_page_mkwrite,
 };
@@ -1215,7 +1213,7 @@ static int btrfs_file_mmap(struct file	*filp, struct vm_area_struct *vma)
         return 0;
 }
 
-struct file_operations btrfs_file_operations = {
+const struct file_operations btrfs_file_operations = {
         .llseek         = generic_file_llseek,
         .read           = do_sync_read,
         .aio_read       = generic_file_aio_read,