Btrfs: check return value of alloc_extent_map()

I add the check on the return value of alloc_extent_map() to several places.
In addition, alloc_extent_map() returns only the address or NULL.
Therefore, check by IS_ERR() is unnecessary. So, I remove IS_ERR() checking.

Signed-off-by: Tsutomu Itoh <t-itoh@jp.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

4 files changed, 7 insertions, 3 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 565e22d77b1b..a7aaa10c5302 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -6584,7 +6584,7 @@ static noinline int relocate_data_extent(struct inode *reloc_inode,
         u64 end = start + extent_key->offset - 1;
 
         em = alloc_extent_map(GFP_NOFS);
-        BUG_ON(!em || IS_ERR(em));
+        BUG_ON(!em);
 
         em->start = start;
         em->len = extent_key->offset;
diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
index b0e1fce12530..2b6c12e983b3 100644
--- a/fs/btrfs/extent_map.c
+++ b/fs/btrfs/extent_map.c
@@ -51,8 +51,8 @@ struct extent_map *alloc_extent_map(gfp_t mask)
 {
         struct extent_map *em;
         em = kmem_cache_alloc(extent_map_cache, mask);
-        if (!em || IS_ERR(em))
-                return em;
+        if (!em)
+                return NULL;
         em->in_tree = 0;
         em->flags = 0;
         em->compress_type = BTRFS_COMPRESS_NONE;
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index b0ff34b96607..65338a1d14ad 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -185,6 +185,7 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
                         split = alloc_extent_map(GFP_NOFS);
                 if (!split2)
                         split2 = alloc_extent_map(GFP_NOFS);
+                BUG_ON(!split || !split2);
 
                 write_lock(&em_tree->lock);
                 em = lookup_extent_mapping(em_tree, start, len);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index c9bc0afdbfc6..8d392ed73d57 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -644,6 +644,7 @@ retry:
                                         async_extent->ram_size - 1, 0);
 
                 em = alloc_extent_map(GFP_NOFS);
+                BUG_ON(!em);
                 em->start = async_extent->start;
                 em->len = async_extent->ram_size;
                 em->orig_start = em->start;
@@ -820,6 +821,7 @@ static noinline int cow_file_range(struct inode *inode,
                 BUG_ON(ret);
 
                 em = alloc_extent_map(GFP_NOFS);
+                BUG_ON(!em);
                 em->start = start;
                 em->orig_start = em->start;
                 ram_size = ins.offset;
@@ -1169,6 +1171,7 @@ out_check:
                         struct extent_map_tree *em_tree;
                         em_tree = &BTRFS_I(inode)->extent_tree;
                         em = alloc_extent_map(GFP_NOFS);
+                        BUG_ON(!em);
                         em->start = cur_offset;
                         em->orig_start = em->start;
                         em->len = num_bytes;