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authorJosef Bacik <josef@redhat.com>2010-11-23 19:36:57 +0000
committerChris Mason <chris.mason@oracle.com>2010-11-27 13:37:50 -0500
commit975f84fee2e8a77ee5f41bfe7c5682bf29366b10 (patch)
treee7e20e775fa4c126273c28d0c7f0ee05b5bb7f5b /fs
parent619c8c763928841b1112e1d417f88bc1d44daecb (diff)
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Btrfs: fix fiemap
There are two big problems currently with FIEMAP 1) We return extents for holes. This isn't supposed to happen, we just don't return extents for holes and then userspace interprets the lack of an extent as a hole. 2) We sometimes don't set FIEMAP_EXTENT_LAST properly. This is because we wait to see a EXTENT_FLAG_VACANCY flag on the em, but this won't happen if say we ask fiemap to map up to the last extent in a file, and there is nothing but holes up to the i_size. To fix this we need to lookup the last extent in this file and save the logical offset, so if we happen to try and map that extent we can be sure to set FIEMAP_EXTENT_LAST. With this patch we now pass xfstest 225, which we never have before. Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/extent_io.c63
1 files changed, 54 insertions, 9 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 143d3f541d6..5e7a94d7da8 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2901,21 +2901,53 @@ out:
int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
__u64 start, __u64 len, get_extent_t *get_extent)
{
- int ret;
+ int ret = 0;
u64 off = start;
u64 max = start + len;
u32 flags = 0;
+ u32 found_type;
+ u64 last;
u64 disko = 0;
+ struct btrfs_key found_key;
struct extent_map *em = NULL;
struct extent_state *cached_state = NULL;
+ struct btrfs_path *path;
+ struct btrfs_file_extent_item *item;
int end = 0;
u64 em_start = 0, em_len = 0;
unsigned long emflags;
- ret = 0;
+ int hole = 0;
if (len == 0)
return -EINVAL;
+ path = btrfs_alloc_path();
+ if (!path)
+ return -ENOMEM;
+ path->leave_spinning = 1;
+
+ ret = btrfs_lookup_file_extent(NULL, BTRFS_I(inode)->root,
+ path, inode->i_ino, -1, 0);
+ if (ret < 0) {
+ btrfs_free_path(path);
+ return ret;
+ }
+ WARN_ON(!ret);
+ path->slots[0]--;
+ item = btrfs_item_ptr(path->nodes[0], path->slots[0],
+ struct btrfs_file_extent_item);
+ btrfs_item_key_to_cpu(path->nodes[0], &found_key, path->slots[0]);
+ found_type = btrfs_key_type(&found_key);
+
+ /* No extents, just return */
+ if (found_key.objectid != inode->i_ino ||
+ found_type != BTRFS_EXTENT_DATA_KEY) {
+ btrfs_free_path(path);
+ return 0;
+ }
+ last = found_key.offset;
+ btrfs_free_path(path);
+
lock_extent_bits(&BTRFS_I(inode)->io_tree, start, start + len, 0,
&cached_state, GFP_NOFS);
em = get_extent(inode, NULL, 0, off, max - off, 0);
@@ -2925,11 +2957,18 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
ret = PTR_ERR(em);
goto out;
}
+
while (!end) {
+ hole = 0;
off = em->start + em->len;
if (off >= max)
end = 1;
+ if (em->block_start == EXTENT_MAP_HOLE) {
+ hole = 1;
+ goto next;
+ }
+
em_start = em->start;
em_len = em->len;
@@ -2939,8 +2978,6 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
if (em->block_start == EXTENT_MAP_LAST_BYTE) {
end = 1;
flags |= FIEMAP_EXTENT_LAST;
- } else if (em->block_start == EXTENT_MAP_HOLE) {
- flags |= FIEMAP_EXTENT_UNWRITTEN;
} else if (em->block_start == EXTENT_MAP_INLINE) {
flags |= (FIEMAP_EXTENT_DATA_INLINE |
FIEMAP_EXTENT_NOT_ALIGNED);
@@ -2953,10 +2990,10 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
if (test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
flags |= FIEMAP_EXTENT_ENCODED;
+next:
emflags = em->flags;
free_extent_map(em);
em = NULL;
-
if (!end) {
em = get_extent(inode, NULL, 0, off, max - off, 0);
if (!em)
@@ -2967,15 +3004,23 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
}
emflags = em->flags;
}
+
if (test_bit(EXTENT_FLAG_VACANCY, &emflags)) {
flags |= FIEMAP_EXTENT_LAST;
end = 1;
}
- ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
- em_len, flags);
- if (ret)
- goto out_free;
+ if (em_start == last) {
+ flags |= FIEMAP_EXTENT_LAST;
+ end = 1;
+ }
+
+ if (!hole) {
+ ret = fiemap_fill_next_extent(fieinfo, em_start, disko,
+ em_len, flags);
+ if (ret)
+ goto out_free;
+ }
}
out_free:
free_extent_map(em);