btrfs-progs: Use more loose open ctree flags for dump-tree and restore
PATCH 1/1 btrfs-progs: Use more loose open ctree flags for dump-tree and restore
Corrupted extent tree (either the root node or leaf) can normally block us from open the fs.
As normally open_ctree() has the following call chain:__open_ctree_fd()
|- btrfs_setup_all_roots()
|- btrfs_read_block_groups()
And we will search block group items in extent tree.
And considering how block group items are scattered around the whole extent tree, any error would block the fs from being mounted.
Fortunately, we already have OPEN_CTREE_NO_BLOCK_GROUPS flags to disable block group items search, which will not only allow us to open some fs, but also hugely speed up open time.
Currently dump-tree and btrfs-restore is ensured that they care nothing about block group items. So specify OPEN_CTREE_NO_BLOCK_GROUPS flag as default.
Also fix a typo where dump-tree is using OPEN_CTREE_FS_PARTIAL, which should be OPEN_CTREE_PARTIAL.
This makes dump-tree do more check and can sometimes fail to open certain filesystems.
--- cmds-inspect-dump-tree.c | 4 +++- cmds-restore.c | 3 ++- 2 files changed, 5 insertions(+), 2 deletions(-)
cmds-inspect-dump-tree.c +3 -1
@@ -303,7 +303,9 @@ int cmd_inspect_dump_tree(int argc, char **argv)int uuid_tree_only =0 ;int roots_only =0 ;int root_backups =0 ; -unsigned open_ctree_flags =OPEN_CTREE_FS_PARTIAL ; +/* Speed up open_ctree() and continue if extent tree is corrupted */ +unsigned open_ctree_flags =OPEN_CTREE_PARTIAL | +OPEN_CTREE_NO_BLOCK_GROUPS ;u64 block_bytenr;struct btrfs_root *tree_root_scan;u64 tree_id =0 ;
cmds-restore.c +2 -1
@@ -1282,7 +1282,8 @@ static struct btrfs_root *open_fs(const char *dev, u64 root_location,for (i = super_mirror; i <BTRFS_SUPER_MIRROR_MAX ; i++) { bytenr =btrfs_sb_offset (i); fs_info =open_ctree_fs_info (dev, bytenr, root_location,0 , -OPEN_CTREE_PARTIAL ); +OPEN_CTREE_PARTIAL | +OPEN_CTREE_NO_BLOCK_GROUPS );if (fs_info)break ;fprintf (stderr,"Could not open root, trying backup super\n" );
Signature · 1 line
2.17.0
Quoted 15 lines · Qu Wenruo
Corrupted extent tree (either the root node or leaf) can normally block us from open the fs.
As normallyopen_ctree()has the following call chain:__open_ctree_fd()
|-btrfs_setup_all_roots()
|-btrfs_read_block_groups()
And we will search block group items in extent tree.And considering how block group items are scattered around the whole extent tree, any error would block the fs from being mounted.
Fortunately, we already have
OPEN_CTREE_NO_BLOCK_GROUPSflags to disable block group items search, which will not only allow us to open some fs, but also hugely speed up open time.
Quoted 8 lines
Currently dump-tree and btrfs-restore is ensured that they care nothing about block group items. So specify
OPEN_CTREE_NO_BLOCK_GROUPSflag as default.Also fix a typo where dump-tree is using
OPEN_CTREE_FS_PARTIAL, which should beOPEN_CTREE_PARTIAL.
This makes dump-tree do more check and can sometimes fail to open certain filesystems.
Oh, that's too easy to get wrong, we should rename one or the other.
Quoted 13 lines
Reported-by Christoph Anton Mitterer <[email protected]>Fixes 8698a2b9ba89 ("btrfs-progs: Allow inspect dump-tree to show specified tree block even some tree roots are corrupted")Signed-off-by Qu Wenruo <[email protected]>--- cmds-inspect-dump-tree.c | 4 +++- cmds-restore.c | 3 ++- 2 files changed, 5 insertions(+), 2 deletions(-)cmds-inspect-dump-tree.c +0
-0
cmds-inspect-dump-tree.c int cmd_inspect_dump_tree(int argc, char **argv) · line 308
Quoted 7 lines
cmds-inspect-dump-tree.c +3
-1@@ -303,7 +303,9 @@ int cmd_inspect_dump_tree(int argc, char **argv)int uuid_tree_only =0 ;int roots_only =0 ;int root_backups =0 ; -unsigned open_ctree_flags =OPEN_CTREE_FS_PARTIAL ; +/* Speed up open_ctree() and continue if extent tree is corrupted */ +unsigned open_ctree_flags =OPEN_CTREE_PARTIAL | +OPEN_CTREE_NO_BLOCK_GROUPS ;
We could consider that separatelly, whether to allow dumping a partially created filesystem, ie. OPEN_CTREE_FS_PARTIAL added by a new option. This would be really for debugging/testing purposes, but could be useful when the filesystem is prefilled with files or if we enable the runtime features and the final write fails for some reason.
Quoted 17 lines
cmds-inspect-dump-tree.c +0
-0u64 block_bytenr;struct btrfs_root *tree_root_scan;u64 tree_id =0 ;cmds-restore.c +2
-1@@ -1282,7 +1282,8 @@ static struct btrfs_root *open_fs(const char *dev, u64 root_location,for (i = super_mirror; i <BTRFS_SUPER_MIRROR_MAX ; i++) { bytenr =btrfs_sb_offset (i); fs_info =open_ctree_fs_info (dev, bytenr, root_location,0 , -OPEN_CTREE_PARTIAL ); +OPEN_CTREE_PARTIAL | +OPEN_CTREE_NO_BLOCK_GROUPS );if (fs_info)break ;fprintf (stderr,"Could not open root, trying backup super\n" );
Quoted 20 lines · David Sterba
Quoted 19 lines · Qu Wenruo
Corrupted extent tree (either the root node or leaf) can normally block us from open the fs.
As normallyopen_ctree()has the following call chain:__open_ctree_fd()
|-btrfs_setup_all_roots()
|-btrfs_read_block_groups()
And we will search block group items in extent tree.And considering how block group items are scattered around the whole extent tree, any error would block the fs from being mounted.
Fortunately, we already have
OPEN_CTREE_NO_BLOCK_GROUPSflags to disable block group items search, which will not only allow us to open some fs, but also hugely speed up open time.Currently dump-tree and btrfs-restore is ensured that they care nothing about block group items. So specify
OPEN_CTREE_NO_BLOCK_GROUPSflag as default.
Quoted 6 lines
Quoted 4 lines
Also fix a typo where dump-tree is using
OPEN_CTREE_FS_PARTIAL, which should beOPEN_CTREE_PARTIAL.
This makes dump-tree do more check and can sometimes fail to open certain filesystems.Oh, that's too easy to get wrong, we should rename one or the other.
Of course, I'll add extra patches for this.
Quoted 9 lines
Quoted 9 lines
Reported-by Christoph Anton Mitterer <[email protected]>Fixes 8698a2b9ba89 ("btrfs-progs: Allow inspect dump-tree to show specified tree block even some tree roots are corrupted")Signed-off-by Qu Wenruo <[email protected]>--- cmds-inspect-dump-tree.c | 4 +++- cmds-restore.c | 3 ++- 2 files changed, 5 insertions(+), 2 deletions(-)
Quoted 15 lines
cmds-inspect-dump-tree.c int cmd_inspect_dump_tree(int argc, char **argv) · line 308
Quoted 12 lines
cmds-inspect-dump-tree.c +3
-1@@ -303,7 +303,9 @@ int cmd_inspect_dump_tree(int argc, char **argv)int uuid_tree_only =0 ;int roots_only =0 ;int root_backups =0 ; -unsigned open_ctree_flags =OPEN_CTREE_FS_PARTIAL ; +/* Speed up open_ctree() and continue if extent tree is corrupted */ +unsigned open_ctree_flags =OPEN_CTREE_PARTIAL | +OPEN_CTREE_NO_BLOCK_GROUPS ;We could consider that separatelly, whether to allow dumping a partially created filesystem, ie.
OPEN_CTREE_FS_PARTIALadded by a new option.
For dump-tree, there is really no limitation here. As long as chunk tree is OK, we should be OK to do "-b" dump.
For "-t" or all tree (default) dump, with chunk tree opened only, we could try our best to print any good trees.
So I don't get the point to read all other trees.
Thanks,
Qu
Quoted 27 lines
This would be really for debugging/testing purposes, but could be useful when the filesystem is prefilled with files or if we enable the runtime features and the final write fails for some reason.
Quoted 8 lines
cmds-inspect-dump-tree.c +0
-0u64 block_bytenr;struct btrfs_root *tree_root_scan;u64 tree_id =0 ;cmds-restore.c +0
-0cmds-restore.c static struct btrfs_root *open_fs(const char *dev, u64 root_location, · line 1289
Quoted 9 lines
cmds-restore.c +2
-1@@ -1282,7 +1282,8 @@ static struct btrfs_root *open_fs(const char *dev, u64 root_location,for (i = super_mirror; i <BTRFS_SUPER_MIRROR_MAX ; i++) { bytenr =btrfs_sb_offset (i); fs_info =open_ctree_fs_info (dev, bytenr, root_location,0 , -OPEN_CTREE_PARTIAL ); +OPEN_CTREE_PARTIAL | +OPEN_CTREE_NO_BLOCK_GROUPS );if (fs_info)break ;fprintf (stderr,"Could not open root, trying backup super\n" );--
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Quoted 14 lines · Qu Wenruo
Quoted 5 lines
Quoted 5 lines
cmds-inspect-dump-tree.c +0
-0@@ -303,7 +303,9 @@ int cmd_inspect_dump_tree(int argc, char **argv)int uuid_tree_only =0 ;int roots_only =0 ;Quoted 8 lines
cmds-inspect-dump-tree.c int cmd_inspect_dump_tree(int argc, char **argv) · line 308
Quoted 5 lines
cmds-inspect-dump-tree.c +3
-1int root_backups =0 ; -unsigned open_ctree_flags =OPEN_CTREE_FS_PARTIAL ; +/* Speed up open_ctree() and continue if extent tree is corrupted */ +unsigned open_ctree_flags =OPEN_CTREE_PARTIAL | +OPEN_CTREE_NO_BLOCK_GROUPS ;We could consider that separatelly, whether to allow dumping a partially created filesystem, ie.
OPEN_CTREE_FS_PARTIALadded by a new option.
Quoted 6 lines
For dump-tree, there is really no limitation here. As long as chunk tree is OK, we should be OK to do "-b" dump.
For "-t" or all tree (default) dump, with chunk tree opened only, we could try our best to print any good trees.
So I don't get the point to read all other trees.
Yeah, eg. a bad filesystem magic number does not stop dump-tree, so no change is needed.
Quoted 18 lines · David Sterba
Quoted 17 lines · Qu Wenruo
Quoted 5 lines
Quoted 5 lines
cmds-inspect-dump-tree.c +0
-0@@ -303,7 +303,9 @@ int cmd_inspect_dump_tree(int argc, char **argv)int uuid_tree_only =0 ;int roots_only =0 ;Quoted 8 lines
cmds-inspect-dump-tree.c int cmd_inspect_dump_tree(int argc, char **argv) · line 308
Quoted 5 lines
cmds-inspect-dump-tree.c +3
-1int root_backups =0 ; -unsigned open_ctree_flags =OPEN_CTREE_FS_PARTIAL ; +/* Speed up open_ctree() and continue if extent tree is corrupted */ +unsigned open_ctree_flags =OPEN_CTREE_PARTIAL | +OPEN_CTREE_NO_BLOCK_GROUPS ;We could consider that separatelly, whether to allow dumping a partially created filesystem, ie.
OPEN_CTREE_FS_PARTIALadded by a new option.For dump-tree, there is really no limitation here. As long as chunk tree is OK, we should be OK to do "-b" dump.
Quoted 6 lines
Quoted 3 lines
For "-t" or all tree (default) dump, with chunk tree opened only, we could try our best to print any good trees.
So I don't get the point to read all other trees.Yeah, eg. a bad filesystem magic number does not stop dump-tree, so no change is needed.
Bad magic will still stop dump-tree, super block check is not affected by open ctree flags.
The only way to block dump-tree is corrupted chunk tree, which mostly makes the fs garbage.
Even root tree is corrupted, we can still specify bytenr manually to salvage what we need.
The point here is still the same, for read-only operations where we don't care about the cross-reference, there is no need to care about extent tree at all, and skip block group item search could save us a lot of time.
Thanks,
Qu