The iterate_irefs in backref.c is used to build path components from inode
refs. This patch adds code to iterate extended refs as well.
I had modify the callback function signature to abstract out some of the
differences between ref structures. iref_to_path() also needed similar
changes.
Reviewed-by: Jan Schmidt <list.bt...@jan-o-sch.net>
Signed-off-by: Mark Fasheh <mfas...@suse.de>
---
fs/btrfs/backref.c | 134 +++++++++++++++++++++++++++++++++++++++++++---------
fs/btrfs/backref.h | 2 -
2 files changed, 112 insertions(+), 24 deletions(-)
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 658e09c..4a01f7c 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1194,11 +1194,10 @@ int btrfs_find_one_extref(struct btrfs_root *root, u64
inode_objectid,
* value will be smaller than dest. callers must check this!
*/
static char *iref_to_path(struct btrfs_root *fs_root, struct btrfs_path *path,
- struct btrfs_inode_ref *iref,
- struct extent_buffer *eb_in, u64 parent,
- char *dest, u32 size)
+ u32 name_len, unsigned long name_off,
+ struct extent_buffer *eb_in, u64 parent,
+ char *dest, u32 size)
{
- u32 len;
int slot;
u64 next_inum;
int ret;
@@ -1206,17 +1205,17 @@ static char *iref_to_path(struct btrfs_root *fs_root,
struct btrfs_path *path,
struct extent_buffer *eb = eb_in;
struct btrfs_key found_key;
int leave_spinning = path->leave_spinning;
+ struct btrfs_inode_ref *iref;
if (bytes_left >= 0)
dest[bytes_left] = '\0';
path->leave_spinning = 1;
while (1) {
- len = btrfs_inode_ref_name_len(eb, iref);
- bytes_left -= len;
+ bytes_left -= name_len;
if (bytes_left >= 0)
read_extent_buffer(eb, dest + bytes_left,
- (unsigned long)(iref + 1), len);
+ name_off, name_len);
if (eb != eb_in) {
btrfs_tree_read_unlock_blocking(eb);
free_extent_buffer(eb);
@@ -1226,6 +1225,7 @@ static char *iref_to_path(struct btrfs_root *fs_root,
struct btrfs_path *path,
ret = -ENOENT;
if (ret)
break;
+
next_inum = found_key.offset;
/* regular exit ahead */
@@ -1241,8 +1241,11 @@ static char *iref_to_path(struct btrfs_root *fs_root,
struct btrfs_path *path,
btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
}
btrfs_release_path(path);
-
iref = btrfs_item_ptr(eb, slot, struct btrfs_inode_ref);
+
+ name_len = btrfs_inode_ref_name_len(eb, iref);
+ name_off = (unsigned long)(iref + 1);
+
parent = next_inum;
--bytes_left;
if (bytes_left >= 0)
@@ -1531,9 +1534,12 @@ int iterate_inodes_from_logical(u64 logical, struct
btrfs_fs_info *fs_info,
return ret;
}
-static int iterate_irefs(u64 inum, struct btrfs_root *fs_root,
- struct btrfs_path *path,
- iterate_irefs_t *iterate, void *ctx)
+typedef int (iterate_irefs_t)(u64 parent, u32 name_len, unsigned long name_off,
+ struct extent_buffer *eb, void *ctx);
+
+static int iterate_inode_refs(u64 inum, struct btrfs_root *fs_root,
+ struct btrfs_path *path,
+ iterate_irefs_t *iterate, void *ctx)
{
int ret = 0;
int slot;
@@ -1550,7 +1556,7 @@ static int iterate_irefs(u64 inum, struct btrfs_root
*fs_root,
while (!ret) {
path->leave_spinning = 1;
ret = inode_ref_info(inum, parent ? parent+1 : 0, fs_root, path,
- &found_key);
+ &found_key);
if (ret < 0)
break;
if (ret) {
@@ -1578,7 +1584,8 @@ static int iterate_irefs(u64 inum, struct btrfs_root
*fs_root,
"tree %llu\n", cur,
(unsigned long long)found_key.objectid,
(unsigned long long)fs_root->objectid);
- ret = iterate(parent, iref, eb, ctx);
+ ret = iterate(parent, name_len,
+ (unsigned long)(iref + 1), eb, ctx);
if (ret)
break;
len = sizeof(*iref) + name_len;
@@ -1593,12 +1600,98 @@ static int iterate_irefs(u64 inum, struct btrfs_root
*fs_root,
return ret;
}
+static int iterate_inode_extrefs(u64 inum, struct btrfs_root *fs_root,
+ struct btrfs_path *path,
+ iterate_irefs_t *iterate, void *ctx)
+{
+ int ret;
+ int slot;
+ u64 offset = 0;
+ u64 parent;
+ int found = 0;
+ struct extent_buffer *eb;
+ struct btrfs_inode_extref *extref;
+ struct extent_buffer *leaf;
+ u32 item_size;
+ u32 cur_offset;
+ unsigned long ptr;
+
+ while (1) {
+ ret = btrfs_find_one_extref(fs_root, inum, offset, path,
&extref,
+ &offset);
+ if (ret < 0)
+ break;
+ if (ret) {
+ ret = found ? 0 : -ENOENT;
+ break;
+ }
+ ++found;
+
+ slot = path->slots[0];
+ eb = path->nodes[0];
+ /* make sure we can use eb after releasing the path */
+ atomic_inc(&eb->refs);
+
+ btrfs_tree_read_lock(eb);
+ btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
+ btrfs_release_path(path);
+
+ leaf = path->nodes[0];
+ item_size = btrfs_item_size_nr(leaf, path->slots[0]);
+ ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
+ cur_offset = 0;
+
+ while (cur_offset < item_size) {
+ u32 name_len;
+
+ extref = (struct btrfs_inode_extref *)(ptr +
cur_offset);
+ parent = btrfs_inode_extref_parent(eb, extref);
+ name_len = btrfs_inode_extref_name_len(eb, extref);
+ ret = iterate(parent, name_len,
+ (unsigned long)&extref->name, eb, ctx);
+ if (ret)
+ break;
+
+ cur_offset += btrfs_inode_extref_name_len(leaf, extref);
+ cur_offset += sizeof(*extref);
+ }
+ btrfs_tree_read_unlock_blocking(eb);
+ free_extent_buffer(eb);
+
+ offset++;
+ }
+
+ btrfs_release_path(path);
+
+ return ret;
+}
+
+static int iterate_irefs(u64 inum, struct btrfs_root *fs_root,
+ struct btrfs_path *path, iterate_irefs_t *iterate,
+ void *ctx)
+{
+ int ret;
+ int found_refs = 0;
+
+ ret = iterate_inode_refs(inum, fs_root, path, iterate, ctx);
+ if (!ret)
+ ++found_refs;
+ else if (ret != -ENOENT)
+ return ret;
+
+ ret = iterate_inode_extrefs(inum, fs_root, path, iterate, ctx);
+ if (ret == -ENOENT && found_refs)
+ return 0;
+
+ return ret;
+}
+
/*
* returns 0 if the path could be dumped (probably truncated)
* returns <0 in case of an error
*/
-static int inode_to_path(u64 inum, struct btrfs_inode_ref *iref,
- struct extent_buffer *eb, void *ctx)
+static int inode_to_path(u64 inum, u32 name_len, unsigned long name_off,
+ struct extent_buffer *eb, void *ctx)
{
struct inode_fs_paths *ipath = ctx;
char *fspath;
@@ -1611,20 +1704,17 @@ static int inode_to_path(u64 inum, struct
btrfs_inode_ref *iref,
ipath->fspath->bytes_left - s_ptr : 0;
fspath_min = (char *)ipath->fspath->val + (i + 1) * s_ptr;
- fspath = iref_to_path(ipath->fs_root, ipath->btrfs_path, iref, eb,
- inum, fspath_min, bytes_left);
+ fspath = iref_to_path(ipath->fs_root, ipath->btrfs_path, name_len,
+ name_off, eb, inum, fspath_min,
+ bytes_left);
if (IS_ERR(fspath))
return PTR_ERR(fspath);
if (fspath > fspath_min) {
- pr_debug("path resolved: %s\n", fspath);
ipath->fspath->val[i] = (u64)(unsigned long)fspath;
++ipath->fspath->elem_cnt;
ipath->fspath->bytes_left = fspath - fspath_min;
} else {
- pr_debug("missed path, not enough space. missing bytes: %lu, "
- "constructed so far: %s\n",
- (unsigned long)(fspath_min - fspath), fspath_min);
++ipath->fspath->elem_missed;
ipath->fspath->bytes_missing += fspath_min - fspath;
ipath->fspath->bytes_left = 0;
@@ -1646,7 +1736,7 @@ static int inode_to_path(u64 inum, struct btrfs_inode_ref
*iref,
int paths_from_inode(u64 inum, struct inode_fs_paths *ipath)
{
return iterate_irefs(inum, ipath->fs_root, ipath->btrfs_path,
- inode_to_path, ipath);
+ inode_to_path, ipath);
}
struct btrfs_data_container *init_data_container(u32 total_bytes)
diff --git a/fs/btrfs/backref.h b/fs/btrfs/backref.h
index 9f3e251..c80889a 100644
--- a/fs/btrfs/backref.h
+++ b/fs/btrfs/backref.h
@@ -32,8 +32,6 @@ struct inode_fs_paths {
typedef int (iterate_extent_inodes_t)(u64 inum, u64 offset, u64 root,
void *ctx);
-typedef int (iterate_irefs_t)(u64 parent, struct btrfs_inode_ref *iref,
- struct extent_buffer *eb, void *ctx);
int inode_item_info(u64 inum, u64 ioff, struct btrfs_root *fs_root,
struct btrfs_path *path);
--
1.7.7
--
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