btrfs: Change the expanding write sequence to fix snapshot related bug.

[cascardo/linux.git] / fs / btrfs / file.c

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 31e48b9..23f6a9d 100644 (file)
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -804,7 +804,10 @@ next_slot:
                 */
                if (start > key.offset && end < extent_end) {
                        BUG_ON(del_nr > 0);
-                       BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
+                       if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
+                               ret = -EINVAL;
+                               break;
+                       }
 
                        memcpy(&new_key, &key, sizeof(new_key));
                        new_key.offset = start;
@@ -847,7 +850,10 @@ next_slot:
                 *      | -------- extent -------- |
                 */
                if (start <= key.offset && end < extent_end) {
-                       BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
+                       if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
+                               ret = -EINVAL;
+                               break;
+                       }
 
                        memcpy(&new_key, &key, sizeof(new_key));
                        new_key.offset = end;
@@ -870,7 +876,10 @@ next_slot:
                 */
                if (start > key.offset && end >= extent_end) {
                        BUG_ON(del_nr > 0);
-                       BUG_ON(extent_type == BTRFS_FILE_EXTENT_INLINE);
+                       if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
+                               ret = -EINVAL;
+                               break;
+                       }
 
                        btrfs_set_file_extent_num_bytes(leaf, fi,
                                                        start - key.offset);
@@ -1360,11 +1369,11 @@ lock_and_cleanup_extent_if_need(struct inode *inode, struct page **pages,
                struct btrfs_ordered_extent *ordered;
                lock_extent_bits(&BTRFS_I(inode)->io_tree,
                                 start_pos, last_pos, 0, cached_state);
-               ordered = btrfs_lookup_first_ordered_extent(inode, last_pos);
+               ordered = btrfs_lookup_ordered_range(inode, start_pos,
+                                                    last_pos - start_pos + 1);
                if (ordered &&
                    ordered->file_offset + ordered->len > start_pos &&
                    ordered->file_offset <= last_pos) {
-                       btrfs_put_ordered_extent(ordered);
                        unlock_extent_cached(&BTRFS_I(inode)->io_tree,
                                             start_pos, last_pos,
                                             cached_state, GFP_NOFS);
@@ -1372,12 +1381,9 @@ lock_and_cleanup_extent_if_need(struct inode *inode, struct page **pages,
                                unlock_page(pages[i]);
                                page_cache_release(pages[i]);
                        }
-                       ret = btrfs_wait_ordered_range(inode, start_pos,
-                                               last_pos - start_pos + 1);
-                       if (ret)
-                               return ret;
-                       else
-                               return -EAGAIN;
+                       btrfs_start_ordered_extent(inode, ordered, 1);
+                       btrfs_put_ordered_extent(ordered);
+                       return -EAGAIN;
                }
                if (ordered)
                        btrfs_put_ordered_extent(ordered);
@@ -1410,8 +1416,12 @@ static noinline int check_can_nocow(struct inode *inode, loff_t pos,
        u64 num_bytes;
        int ret;
 
+       ret = btrfs_start_nocow_write(root);
+       if (!ret)
+               return -ENOSPC;
+
        lockstart = round_down(pos, root->sectorsize);
-       lockend = lockstart + round_up(*write_bytes, root->sectorsize) - 1;
+       lockend = round_up(pos + *write_bytes, root->sectorsize) - 1;
 
        while (1) {
                lock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
@@ -1429,12 +1439,10 @@ static noinline int check_can_nocow(struct inode *inode, loff_t pos,
        ret = can_nocow_extent(inode, lockstart, &num_bytes, NULL, NULL, NULL);
        if (ret <= 0) {
                ret = 0;
+               btrfs_end_nocow_write(root);
        } else {
-               clear_extent_bit(&BTRFS_I(inode)->io_tree, lockstart, lockend,
-                                EXTENT_DIRTY | EXTENT_DELALLOC |
-                                EXTENT_DO_ACCOUNTING | EXTENT_DEFRAG, 0, 0,
-                                NULL, GFP_NOFS);
-               *write_bytes = min_t(size_t, *write_bytes, num_bytes);
+               *write_bytes = min_t(size_t, *write_bytes ,
+                                    num_bytes - pos + lockstart);
        }
 
        unlock_extent(&BTRFS_I(inode)->io_tree, lockstart, lockend);
@@ -1524,6 +1532,8 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file,
                        if (!only_release_metadata)
                                btrfs_free_reserved_data_space(inode,
                                                               reserve_bytes);
+                       else
+                               btrfs_end_nocow_write(root);
                        break;
                }
 
@@ -1612,6 +1622,9 @@ again:
                }
 
                release_bytes = 0;
+               if (only_release_metadata)
+                       btrfs_end_nocow_write(root);
+
                if (only_release_metadata && copied > 0) {
                        u64 lockstart = round_down(pos, root->sectorsize);
                        u64 lockend = lockstart +
@@ -1638,10 +1651,12 @@ again:
        kfree(pages);
 
        if (release_bytes) {
-               if (only_release_metadata)
+               if (only_release_metadata) {
+                       btrfs_end_nocow_write(root);
                        btrfs_delalloc_release_metadata(inode, release_bytes);
-               else
+               } else {
                        btrfs_delalloc_release_space(inode, release_bytes);
+               }
        }
 
        return num_written ? num_written : ret;
@@ -1712,6 +1727,7 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
        struct btrfs_root *root = BTRFS_I(inode)->root;
        loff_t *ppos = &iocb->ki_pos;
        u64 start_pos;
+       u64 end_pos;
        ssize_t num_written = 0;
        ssize_t err = 0;
        size_t count, ocount;
@@ -1766,7 +1782,9 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
 
        start_pos = round_down(pos, root->sectorsize);
        if (start_pos > i_size_read(inode)) {
-               err = btrfs_cont_expand(inode, i_size_read(inode), start_pos);
+               /* Expand hole size to cover write data, preventing empty gap */
+               end_pos = round_up(pos + iov->iov_len, root->sectorsize);
+               err = btrfs_cont_expand(inode, i_size_read(inode), end_pos);
                if (err) {
                        mutex_unlock(&inode->i_mutex);
                        goto out;