On Wed, August 08, 2012 at 20:55 (+0200), Mark Fasheh wrote: > 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. > > Signed-off-by: Mark Fasheh <[email protected]> > --- > 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);
Reviewed-by: Jan Schmidt <[email protected]> -Jan -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
