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Btrfs: handle only applicable errors returned by btrfs_get_extent 

btrfs_get_extent() never returns NULL pointers, so this code introduces
a static checker warning.

The btrfs_get_extent() is a bit complex, but trust me that it doesn't
return NULLs and also if it did we would trigger the BUG_ON(!em) before
the last return statement.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
[ updated subject ]
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Dan Carpenter 2017-04-11 11:57:15 +03:00 committed by David Sterba
parent 82bafb38c2
commit 9986277e0e
2 changed files with 15 additions and 26 deletions
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16
fs/btrfs/file.c
View File

@ -2342,13 +2342,8 @@ static int find_first_non_hole(struct inode *inode, u64 *start, u64 *len)
int ret = 0;
em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, *start, *len, 0);
if (IS_ERR_OR_NULL(em)) {
if (!em)
ret = -ENOMEM;
else
ret = PTR_ERR(em);
return ret;
}
if (IS_ERR(em))
return PTR_ERR(em);
/* Hole or vacuum extent(only exists in no-hole mode) */
if (em->block_start == EXTENT_MAP_HOLE) {
@ -2835,11 +2830,8 @@ static long btrfs_fallocate(struct file *file, int mode,
while (1) {
em = btrfs_get_extent(BTRFS_I(inode), NULL, 0, cur_offset,
alloc_end - cur_offset, 0);
if (IS_ERR_OR_NULL(em)) {
if (!em)
ret = -ENOMEM;
else
ret = PTR_ERR(em);
if (IS_ERR(em)) {
ret = PTR_ERR(em);
break;
}
last_byte = min(extent_map_end(em), alloc_end);

25
fs/btrfs/inode.c
View File

@ -6736,7 +6736,6 @@ static noinline int uncompress_inline(struct btrfs_path *path,
*
* This also copies inline extents directly into the page.
*/
struct extent_map *btrfs_get_extent(struct btrfs_inode *inode,
struct page *page,
size_t pg_offset, u64 start, u64 len,
@ -7045,19 +7044,17 @@ struct extent_map *btrfs_get_extent_fiemap(struct btrfs_inode *inode,
em = btrfs_get_extent(inode, page, pg_offset, start, len, create);
if (IS_ERR(em))
return em;
if (em) {
/*
* if our em maps to
* - a hole or
* - a pre-alloc extent,
* there might actually be delalloc bytes behind it.
*/
if (em->block_start != EXTENT_MAP_HOLE &&
!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
return em;
else
hole_em = em;
}
/*
* If our em maps to:
* - a hole or
* - a pre-alloc extent,
* there might actually be delalloc bytes behind it.
*/
if (em->block_start != EXTENT_MAP_HOLE &&
!test_bit(EXTENT_FLAG_PREALLOC, &em->flags))
return em;
else
hole_em = em;
/* check to see if we've wrapped (len == -1 or similar) */
end = start + len;