ext4: fix EOFBLOCKS_FL handling
It turns out we have several problems with how EOFBLOCKS_FL is
handled. First of all, there was a fencepost error where we were not
clearing the EOFBLOCKS_FL when fill in the last uninitialized block,
but rather when we allocate the next block _after_ the uninitalized
block. Secondly we were not testing to see if we needed to clear the
EOFBLOCKS_FL when writing to the file O_DIRECT or when were converting
an uninitialized block (which is the most common case).
Google-Bug-Id: 2928259
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 06328d3..8202784 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3180,6 +3180,57 @@
unmap_underlying_metadata(bdev, block + i);
}
+/*
+ * Handle EOFBLOCKS_FL flag, clearing it if necessary
+ */
+static int check_eofblocks_fl(handle_t *handle, struct inode *inode,
+ struct ext4_map_blocks *map,
+ struct ext4_ext_path *path,
+ unsigned int len)
+{
+ int i, depth;
+ struct ext4_extent_header *eh;
+ struct ext4_extent *ex, *last_ex;
+
+ if (!ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
+ return 0;
+
+ depth = ext_depth(inode);
+ eh = path[depth].p_hdr;
+ ex = path[depth].p_ext;
+
+ if (unlikely(!eh->eh_entries)) {
+ EXT4_ERROR_INODE(inode, "eh->eh_entries == 0 and "
+ "EOFBLOCKS_FL set");
+ return -EIO;
+ }
+ last_ex = EXT_LAST_EXTENT(eh);
+ /*
+ * We should clear the EOFBLOCKS_FL flag if we are writing the
+ * last block in the last extent in the file. We test this by
+ * first checking to see if the caller to
+ * ext4_ext_get_blocks() was interested in the last block (or
+ * a block beyond the last block) in the current extent. If
+ * this turns out to be false, we can bail out from this
+ * function immediately.
+ */
+ if (map->m_lblk + len < le32_to_cpu(last_ex->ee_block) +
+ ext4_ext_get_actual_len(last_ex))
+ return 0;
+ /*
+ * If the caller does appear to be planning to write at or
+ * beyond the end of the current extent, we then test to see
+ * if the current extent is the last extent in the file, by
+ * checking to make sure it was reached via the rightmost node
+ * at each level of the tree.
+ */
+ for (i = depth-1; i >= 0; i--)
+ if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
+ return 0;
+ ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
+ return ext4_mark_inode_dirty(handle, inode);
+}
+
static int
ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
struct ext4_map_blocks *map,
@@ -3217,8 +3268,12 @@
if ((flags & EXT4_GET_BLOCKS_CONVERT)) {
ret = ext4_convert_unwritten_extents_endio(handle, inode,
path);
- if (ret >= 0)
+ if (ret >= 0) {
ext4_update_inode_fsync_trans(handle, inode, 1);
+ err = check_eofblocks_fl(handle, inode, map, path,
+ map->m_len);
+ } else
+ err = ret;
goto out2;
}
/* buffered IO case */
@@ -3244,8 +3299,13 @@
/* buffered write, writepage time, convert*/
ret = ext4_ext_convert_to_initialized(handle, inode, map, path);
- if (ret >= 0)
+ if (ret >= 0) {
ext4_update_inode_fsync_trans(handle, inode, 1);
+ err = check_eofblocks_fl(handle, inode, map, path, map->m_len);
+ if (err < 0)
+ goto out2;
+ }
+
out:
if (ret <= 0) {
err = ret;
@@ -3292,6 +3352,7 @@
}
return err ? err : allocated;
}
+
/*
* Block allocation/map/preallocation routine for extents based files
*
@@ -3315,9 +3376,9 @@
{
struct ext4_ext_path *path = NULL;
struct ext4_extent_header *eh;
- struct ext4_extent newex, *ex, *last_ex;
+ struct ext4_extent newex, *ex;
ext4_fsblk_t newblock;
- int i, err = 0, depth, ret, cache_type;
+ int err = 0, depth, ret, cache_type;
unsigned int allocated = 0;
struct ext4_allocation_request ar;
ext4_io_end_t *io = EXT4_I(inode)->cur_aio_dio;
@@ -3497,31 +3558,10 @@
map->m_flags |= EXT4_MAP_UNINIT;
}
- if (unlikely(ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))) {
- if (unlikely(!eh->eh_entries)) {
- EXT4_ERROR_INODE(inode,
- "eh->eh_entries == 0 and "
- "EOFBLOCKS_FL set");
- err = -EIO;
- goto out2;
- }
- last_ex = EXT_LAST_EXTENT(eh);
- /*
- * If the current leaf block was reached by looking at
- * the last index block all the way down the tree, and
- * we are extending the inode beyond the last extent
- * in the current leaf block, then clear the
- * EOFBLOCKS_FL flag.
- */
- for (i = depth-1; i >= 0; i--) {
- if (path[i].p_idx != EXT_LAST_INDEX(path[i].p_hdr))
- break;
- }
- if ((i < 0) &&
- (map->m_lblk + ar.len > le32_to_cpu(last_ex->ee_block) +
- ext4_ext_get_actual_len(last_ex)))
- ext4_clear_inode_flag(inode, EXT4_INODE_EOFBLOCKS);
- }
+ err = check_eofblocks_fl(handle, inode, map, path, ar.len);
+ if (err)
+ goto out2;
+
err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
if (err) {
/* free data blocks we just allocated */