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ext4: fix EOFBLOCKS_FL handling

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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>
This commit is contained in:
Theodore Ts'o 2010-10-27 21:23:12 -04:00
parent 899611ee7d
commit 58590b06d7
1 changed files with 69 additions and 29 deletions
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98
fs/ext4/extents.c
View File

@ -3180,6 +3180,57 @@ static void unmap_underlying_metadata_blocks(struct block_device *bdev,
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 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
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 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
/* 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 @@ out2:
}
return err ? err : allocated;
}
/*
* Block allocation/map/preallocation routine for extents based files
*
@ -3315,9 +3376,9 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
{
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 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
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 */