| Message ID | 20180327070658.13064-6-lufq.fnst@cn.fujitsu.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 2018年03月27日 15:06, Lu Fengqi wrote: > The function will find the root_item specified by the subvol_id, > clear the BTRFS_ROOT_SUBVOL_DEAD flag and set root_refs to one. Sorry I didn't point it out in btrfs_link_subvol() patch, but at least to me, refs should only be modified by btrfs_link_subvol(), just like btrfs_unlink(). Thanks, Qu > > Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com> > --- > ctree.h | 1 + > undelete-subvol.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ > 2 files changed, 56 insertions(+) > > diff --git a/ctree.h b/ctree.h > index 4bff0b821472..7c0b8150bc4e 100644 > --- a/ctree.h > +++ b/ctree.h > @@ -184,6 +184,7 @@ static int btrfs_csum_sizes[] = { 4 }; > #define BTRFS_FT_MAX 9 > > #define BTRFS_ROOT_SUBVOL_RDONLY (1ULL << 0) > +#define BTRFS_ROOT_SUBVOL_DEAD (1ULL << 48) > > /* > * the key defines the order in the tree, and so it also defines (optimal) > diff --git a/undelete-subvol.c b/undelete-subvol.c > index 00fcc4895778..781057df2b84 100644 > --- a/undelete-subvol.c > +++ b/undelete-subvol.c > @@ -12,6 +12,9 @@ > */ > > #include "ctree.h" > +#include "transaction.h" > +#include "disk-io.h" > +#include "messages.h" > > /* > * Determines whether the subvolume is intact, according to the drop_progress > @@ -51,3 +54,55 @@ out: > btrfs_release_path(&path); > return ret; > } > + > +/* > + * Clear BTRFS_ROOT_SUBVOL_DEAD flag and set the root_refs to one. > + * > + * @root the root of root tree. > + * @subvol_id specify the root_item which will be modified. > + * > + * Return 0 if no error occurred. > + */ > +static int recover_dead_root(struct btrfs_trans_handle *trans, > + struct btrfs_root *root, u64 subvol_id) > +{ > + struct btrfs_key key; > + struct btrfs_path path; > + struct extent_buffer *leaf; > + struct btrfs_root_item root_item; > + u64 root_flags; > + u64 offset; > + int ret; > + > + key.objectid = subvol_id; > + key.type = BTRFS_ROOT_ITEM_KEY; > + key.offset = 0; > + > + btrfs_init_path(&path); > + ret = btrfs_search_slot(trans, root, &key, &path, 0, 0); > + if (ret) { > + error("couldn't find ROOT_ITEM for %llu failed: %d", > + subvol_id, ret); > + goto out; > + } > + > + leaf = path.nodes[0]; > + > + offset = btrfs_item_ptr_offset(leaf, path.slots[0]); > + read_extent_buffer(leaf, &root_item, offset, sizeof(root_item)); > + > + /* Clear BTRFS_ROOT_SUBVOL_DEAD */ > + root_flags = btrfs_root_flags(&root_item); > + btrfs_set_root_flags(&root_item, > + root_flags & ~BTRFS_ROOT_SUBVOL_DEAD); > + > + /* Increase the refs */ > + btrfs_set_root_refs(&root_item, 1); > + > + write_extent_buffer(leaf, &root_item, offset, sizeof(root_item)); > + btrfs_mark_buffer_dirty(leaf); > + > +out: > + btrfs_release_path(&path); > + return ret; > +} >
On Wed, Apr 18, 2018 at 01:16:55PM +0800, Qu Wenruo wrote: > > >On 2018年03月27日 15:06, Lu Fengqi wrote: >> The function will find the root_item specified by the subvol_id, >> clear the BTRFS_ROOT_SUBVOL_DEAD flag and set root_refs to one. > >Sorry I didn't point it out in btrfs_link_subvol() patch, but at least >to me, refs should only be modified by btrfs_link_subvol(), just like >btrfs_unlink(). This has bothered me a long time. The function create_subvol has set root_refs to 1 before linking the subvolume in the kernel or btrfs_progs. I would like to modify the refs to 1 in btrfs_link_subvol as you said, regardless of the root_refs of the subvolume is already 1 (only when link_subvol_for_convert is caller).
diff --git a/ctree.h b/ctree.h index 4bff0b821472..7c0b8150bc4e 100644 --- a/ctree.h +++ b/ctree.h @@ -184,6 +184,7 @@ static int btrfs_csum_sizes[] = { 4 }; #define BTRFS_FT_MAX 9 #define BTRFS_ROOT_SUBVOL_RDONLY (1ULL << 0) +#define BTRFS_ROOT_SUBVOL_DEAD (1ULL << 48) /* * the key defines the order in the tree, and so it also defines (optimal) diff --git a/undelete-subvol.c b/undelete-subvol.c index 00fcc4895778..781057df2b84 100644 --- a/undelete-subvol.c +++ b/undelete-subvol.c @@ -12,6 +12,9 @@ */ #include "ctree.h" +#include "transaction.h" +#include "disk-io.h" +#include "messages.h" /* * Determines whether the subvolume is intact, according to the drop_progress @@ -51,3 +54,55 @@ out: btrfs_release_path(&path); return ret; } + +/* + * Clear BTRFS_ROOT_SUBVOL_DEAD flag and set the root_refs to one. + * + * @root the root of root tree. + * @subvol_id specify the root_item which will be modified. + * + * Return 0 if no error occurred. + */ +static int recover_dead_root(struct btrfs_trans_handle *trans, + struct btrfs_root *root, u64 subvol_id) +{ + struct btrfs_key key; + struct btrfs_path path; + struct extent_buffer *leaf; + struct btrfs_root_item root_item; + u64 root_flags; + u64 offset; + int ret; + + key.objectid = subvol_id; + key.type = BTRFS_ROOT_ITEM_KEY; + key.offset = 0; + + btrfs_init_path(&path); + ret = btrfs_search_slot(trans, root, &key, &path, 0, 0); + if (ret) { + error("couldn't find ROOT_ITEM for %llu failed: %d", + subvol_id, ret); + goto out; + } + + leaf = path.nodes[0]; + + offset = btrfs_item_ptr_offset(leaf, path.slots[0]); + read_extent_buffer(leaf, &root_item, offset, sizeof(root_item)); + + /* Clear BTRFS_ROOT_SUBVOL_DEAD */ + root_flags = btrfs_root_flags(&root_item); + btrfs_set_root_flags(&root_item, + root_flags & ~BTRFS_ROOT_SUBVOL_DEAD); + + /* Increase the refs */ + btrfs_set_root_refs(&root_item, 1); + + write_extent_buffer(leaf, &root_item, offset, sizeof(root_item)); + btrfs_mark_buffer_dirty(leaf); + +out: + btrfs_release_path(&path); + return ret; +}
The function will find the root_item specified by the subvol_id, clear the BTRFS_ROOT_SUBVOL_DEAD flag and set root_refs to one. Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com> --- ctree.h | 1 + undelete-subvol.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 56 insertions(+)