1 files changed, 127 insertions, 129 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index dac1fc21d809..09182449cbdf 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5773,18 +5773,109 @@ out:
         return ret;
 }
 
+static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend,
+                              struct extent_state **cached_state, int writing)
+{
+        struct btrfs_ordered_extent *ordered;
+        int ret = 0;
+
+        while (1) {
+                lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
+                                 0, cached_state);
+                /*
+                 * We're concerned with the entire range that we're going to be
+                 * doing DIO to, so we need to make sure theres no ordered
+                 * extents in this range.
+                 */
+                ordered = btrfs_lookup_ordered_range(inode, lockstart,
+                                                     lockend - lockstart + 1);
+
+                /*
+                 * We need to make sure there are no buffered pages in this
+                 * range either, we could have raced between the invalidate in
+                 * generic_file_direct_write and locking the extent.  The
+                 * invalidate needs to happen so that reads after a write do not
+                 * get stale data.
+                 */
+                if (!ordered && (!writing ||
+                    !test_range_bit(&BTRFS_I(inode)->io_tree,
+                                    lockstart, lockend, EXTENT_UPTODATE, 0,
+                                    *cached_state)))
+                        break;
+
+                unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
+                                     cached_state, GFP_NOFS);
+
+                if (ordered) {
+                        btrfs_start_ordered_extent(inode, ordered, 1);
+                        btrfs_put_ordered_extent(ordered);
+                } else {
+                        /* Screw you mmap */
+                        ret = filemap_write_and_wait_range(inode->i_mapping,
+                                                           lockstart,
+                                                           lockend);
+                        if (ret)
+                                break;
+
+                        /*
+                         * If we found a page that couldn't be invalidated just
+                         * fall back to buffered.
+                         */
+                        ret = invalidate_inode_pages2_range(inode->i_mapping,
+                                        lockstart >> PAGE_CACHE_SHIFT,
+                                        lockend >> PAGE_CACHE_SHIFT);
+                        if (ret)
+                                break;
+                }
+
+                cond_resched();
+        }
+
+        return ret;
+}
+
 static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
                                    struct buffer_head *bh_result, int create)
 {
         struct extent_map *em;
         struct btrfs_root *root = BTRFS_I(inode)->root;
+        struct extent_state *cached_state = NULL;
         u64 start = iblock << inode->i_blkbits;
+        u64 lockstart, lockend;
         u64 len = bh_result->b_size;
         struct btrfs_trans_handle *trans;
+        int unlock_bits = EXTENT_LOCKED;
+        int ret;
+
+        lockstart = start;
+        lockend = start + len - 1;
+        if (create) {
+                ret = btrfs_delalloc_reserve_space(inode, len);
+                if (ret)
+                        return ret;
+                unlock_bits |= EXTENT_DELALLOC | EXTENT_DIRTY;
+        }
+
+        /*
+         * If this errors out it's because we couldn't invalidate pagecache for
+         * this range and we need to fallback to buffered.
+         */
+        if (lock_extent_direct(inode, lockstart, lockend, &cached_state, create))
+                return -ENOTBLK;
+
+        if (create) {
+                ret = set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
+                                     lockend, EXTENT_DELALLOC, NULL,
+                                     &cached_state, GFP_NOFS);
+                if (ret)
+                        goto unlock_err;
+        }
 
         em = btrfs_get_extent(inode, NULL, 0, start, len, 0);
-        if (IS_ERR(em))
-                return PTR_ERR(em);
+        if (IS_ERR(em)) {
+                ret = PTR_ERR(em);
+                goto unlock_err;
+        }
 
         /*
          * Ok for INLINE and COMPRESSED extents we need to fallback on buffered
@@ -5803,17 +5894,16 @@ static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
         if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags) ||
             em->block_start == EXTENT_MAP_INLINE) {
                 free_extent_map(em);
-                return -ENOTBLK;
+                ret = -ENOTBLK;
+                goto unlock_err;
         }
 
         /* Just a good old fashioned hole, return */
         if (!create && (em->block_start == EXTENT_MAP_HOLE ||
                         test_bit(EXTENT_FLAG_PREALLOC, &em->flags))) {
                 free_extent_map(em);
-                /* DIO will do one hole at a time, so just unlock a sector */
-                unlock_extent(&BTRFS_I(inode)->io_tree, start,
-                              start + root->sectorsize - 1);
-                return 0;
+                ret = 0;
+                goto unlock_err;
         }
 
         /*
@@ -5826,8 +5916,9 @@ static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
          *
          */
         if (!create) {
-                len = em->len - (start - em->start);
-                goto map;
+                len = min(len, em->len - (start - em->start));
+                lockstart = start + len;
+                goto unlock;
         }
 
         if (test_bit(EXTENT_FLAG_PREALLOC, &em->flags) ||
@@ -5859,7 +5950,7 @@ static int btrfs_get_blocks_direct(struct inode *inode, sector_t iblock,
                         btrfs_end_transaction(trans, root);
                         if (ret) {
                                 free_extent_map(em);
-                                return ret;
+                                goto unlock_err;
                         }
                         goto unlock;
                 }
@@ -5872,14 +5963,12 @@ must_cow:
          */
         len = bh_result->b_size;
         em = btrfs_new_extent_direct(inode, em, start, len);
-        if (IS_ERR(em))
-                return PTR_ERR(em);
+        if (IS_ERR(em)) {
+                ret = PTR_ERR(em);
+                goto unlock_err;
+        }
         len = min(len, em->len - (start - em->start));
 unlock:
-        clear_extent_bit(&BTRFS_I(inode)->io_tree, start, start + len - 1,
-                          EXTENT_LOCKED | EXTENT_DELALLOC | EXTENT_DIRTY, 1,
-                          0, NULL, GFP_NOFS);
-map:
         bh_result->b_blocknr = (em->block_start + (start - em->start)) >>
                 inode->i_blkbits;
         bh_result->b_size = len;
@@ -5897,9 +5986,28 @@ map:
                         i_size_write(inode, start + len);
         }
 
+        /*
+         * In the case of write we need to clear and unlock the entire range,
+         * in the case of read we need to unlock only the end area that we
+         * aren't using if there is any left over space.
+         */
+        if (lockstart < lockend)
+                clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
+                                 unlock_bits, 1, 0, &cached_state, GFP_NOFS);
+        else
+                free_extent_state(cached_state);
+
         free_extent_map(em);
 
         return 0;
+
+unlock_err:
+        if (create)
+                unlock_bits |= EXTENT_DO_ACCOUNTING;
+
+        clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
+                         unlock_bits, 1, 0, &cached_state, GFP_NOFS);
+        return ret;
 }
 
 struct btrfs_dio_private {
@@ -6340,132 +6448,22 @@ static ssize_t check_direct_IO(struct btrfs_root *root, int rw, struct kiocb *io
 out:
         return retval;
 }
+
 static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
                         const struct iovec *iov, loff_t offset,
                         unsigned long nr_segs)
 {
         struct file *file = iocb->ki_filp;
         struct inode *inode = file->f_mapping->host;
-        struct btrfs_ordered_extent *ordered;
-        struct extent_state *cached_state = NULL;
-        u64 lockstart, lockend;
-        ssize_t ret;
-        int writing = rw & WRITE;
-        int write_bits = 0;
-        size_t count = iov_length(iov, nr_segs);
 
         if (check_direct_IO(BTRFS_I(inode)->root, rw, iocb, iov,
-                            offset, nr_segs)) {
+                            offset, nr_segs))
                 return 0;
-        }
-
-        lockstart = offset;
-        lockend = offset + count - 1;
-
-        if (writing) {
-                ret = btrfs_delalloc_reserve_space(inode, count);
-                if (ret)
-                        goto out;
-        }
 
-        while (1) {
-                lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,
-                                 0, &cached_state);
-                /*
-                 * We're concerned with the entire range that we're going to be
-                 * doing DIO to, so we need to make sure theres no ordered
-                 * extents in this range.
-                 */
-                ordered = btrfs_lookup_ordered_range(inode, lockstart,
-                                                     lockend - lockstart + 1);
-
-                /*
-                 * We need to make sure there are no buffered pages in this
-                 * range either, we could have raced between the invalidate in
-                 * generic_file_direct_write and locking the extent.  The
-                 * invalidate needs to happen so that reads after a write do not
-                 * get stale data.
-                 */
-                if (!ordered && (!writing ||
-                    !test_range_bit(&BTRFS_I(inode)->io_tree,
-                                    lockstart, lockend, EXTENT_UPTODATE, 0,
-                                    cached_state)))
-                        break;
-
-                unlock_extent_cached(&BTRFS_I(inode)->io_tree, lockstart, lockend,
-                                     &cached_state, GFP_NOFS);
-
-                if (ordered) {
-                        btrfs_start_ordered_extent(inode, ordered, 1);
-                        btrfs_put_ordered_extent(ordered);
-                } else {
-                        /* Screw you mmap */
-                        ret = filemap_write_and_wait_range(file->f_mapping,
-                                                           lockstart,
-                                                           lockend);
-                        if (ret)
-                                goto out;
-
-                        /*
-                         * If we found a page that couldn't be invalidated just
-                         * fall back to buffered.
-                         */
-                        ret = invalidate_inode_pages2_range(file->f_mapping,
-                                        lockstart >> PAGE_CACHE_SHIFT,
-                                        lockend >> PAGE_CACHE_SHIFT);
-                        if (ret) {
-                                if (ret == -EBUSY)
-                                        ret = 0;
-                                goto out;
-                        }
-                }
-
-                cond_resched();
-        }
-
-        /*
-         * we don't use btrfs_set_extent_delalloc because we don't want
-         * the dirty or uptodate bits
-         */
-        if (writing) {
-                write_bits = EXTENT_DELALLOC | EXTENT_DO_ACCOUNTING;
-                ret = set_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
-                                     EXTENT_DELALLOC, NULL, &cached_state,
-                                     GFP_NOFS);
-                if (ret) {
-                        clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart,
-                                         lockend, EXTENT_LOCKED | write_bits,
-                                         1, 0, &cached_state, GFP_NOFS);
-                        goto out;
-                }
-        }
-
-        free_extent_state(cached_state);
-        cached_state = NULL;
-
-        ret = __blockdev_direct_IO(rw, iocb, inode,
+        return __blockdev_direct_IO(rw, iocb, inode,
                    BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev,
                    iov, offset, nr_segs, btrfs_get_blocks_direct, NULL,
                    btrfs_submit_direct, 0);
-
-        if (ret < 0 && ret != -EIOCBQUEUED) {
-                clear_extent_bit(&BTRFS_I(inode)->io_tree, offset,
-                              offset + iov_length(iov, nr_segs) - 1,
-                              EXTENT_LOCKED | write_bits, 1, 0,
-                              &cached_state, GFP_NOFS);
-        } else if (ret >= 0 && ret < iov_length(iov, nr_segs)) {
-                /*
-                 * We're falling back to buffered, unlock the section we didn't
-                 * do IO on.
-                 */
-                clear_extent_bit(&BTRFS_I(inode)->io_tree, offset + ret,
-                              offset + iov_length(iov, nr_segs) - 1,
-                              EXTENT_LOCKED | write_bits, 1, 0,
-                              &cached_state, GFP_NOFS);
-        }
-out:
-        free_extent_state(cached_state);
-        return ret;
 }
 
 static int btrfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,