On Fri, Mar 02, 2018 at 11:29:33AM -0700, Liu Bo wrote:
> On Wed, Feb 28, 2018 at 03:56:10PM +0000, fdman...@kernel.org wrote:
> > From: Filipe Manana <fdman...@suse.com>
> >
> > If we have a file with 2 (or more) hard links in the same directory,
> > remove one of the hard links, create a new file (or link an existing file)
> > in the same directory with the name of the removed hard link, and then
> > finally fsync the new file, we end up with a log that fails to replay,
> > causing a mount failure.
> >
> > Example:
> >
> > $ mkfs.btrfs -f /dev/sdb
> > $ mount /dev/sdb /mnt
> >
> > $ mkdir /mnt/testdir
> > $ touch /mnt/testdir/foo
> > $ ln /mnt/testdir/foo /mnt/testdir/bar
> >
> > $ sync
> >
> > $ unlink /mnt/testdir/bar
> > $ touch /mnt/testdir/bar
So here, "unlink & touch" similar to rename, therefore we could also
be conservative and set /mnt/testdir 's last_unlink_trans to force to
commit transaction.
Thanks,
-liubo
> > $ xfs_io -c "fsync" /mnt/testdir/bar
> >
> > <power failure>
> >
> > $ mount /dev/sdb /mnt
> > mount: mount(2) failed: /mnt: No such file or directory
> >
> > When replaying the log, for that example, we also see the following in
> > dmesg/syslog:
> >
> > [71813.671307] BTRFS info (device dm-0): failed to delete reference to
> > bar, inode 258 parent 257
> > [71813.674204] ------------[ cut here ]------------
> > [71813.675694] BTRFS: Transaction aborted (error -2)
> > [71813.677236] WARNING: CPU: 1 PID: 13231 at fs/btrfs/inode.c:4128
> > __btrfs_unlink_inode+0x17b/0x355 [btrfs]
> > [71813.679669] Modules linked in: btrfs xfs f2fs dm_flakey dm_mod dax
> > ghash_clmulni_intel ppdev pcbc aesni_intel aes_x86_64 crypto_simd cryptd
> > glue_helper evdev psmouse i2c_piix4 parport_pc i2c_core pcspkr sg serio_raw
> > parport button sunrpc loop autofs4 ext4 crc16 mbcache jbd2 zstd_decompress
> > zstd_compress xxhash raid10 raid456 async_raid6_recov async_memcpy async_pq
> > async_xor async_tx xor raid6_pq libcrc32c crc32c_generic raid1 raid0
> > multipath linear md_mod ata_generic sd_mod virtio_scsi ata_piix libata
> > virtio_pci virtio_ring crc32c_intel floppy virtio e1000 scsi_mod [last
> > unloaded: btrfs]
> > [71813.679669] CPU: 1 PID: 13231 Comm: mount Tainted: G W
> > 4.15.0-rc9-btrfs-next-56+ #1
> > [71813.679669] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
> > BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
> > [71813.679669] RIP: 0010:__btrfs_unlink_inode+0x17b/0x355 [btrfs]
> > [71813.679669] RSP: 0018:ffffc90001cef738 EFLAGS: 00010286
> > [71813.679669] RAX: 0000000000000025 RBX: ffff880217ce4708 RCX:
> > 0000000000000001
> > [71813.679669] RDX: 0000000000000000 RSI: ffffffff81c14bae RDI:
> > 00000000ffffffff
> > [71813.679669] RBP: ffffc90001cef7c0 R08: 0000000000000001 R09:
> > 0000000000000001
> > [71813.679669] R10: ffffc90001cef5e0 R11: ffffffff8343f007 R12:
> > ffff880217d474c8
> > [71813.679669] R13: 00000000fffffffe R14: ffff88021ccf1548 R15:
> > 0000000000000101
> > [71813.679669] FS: 00007f7cee84c480(0000) GS:ffff88023fc80000(0000)
> > knlGS:0000000000000000
> > [71813.679669] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [71813.679669] CR2: 00007f7cedc1abf9 CR3: 00000002354b4003 CR4:
> > 00000000001606e0
> > [71813.679669] Call Trace:
> > [71813.679669] btrfs_unlink_inode+0x17/0x41 [btrfs]
> > [71813.679669] drop_one_dir_item+0xfa/0x131 [btrfs]
> > [71813.679669] add_inode_ref+0x71e/0x851 [btrfs]
> > [71813.679669] ? __lock_is_held+0x39/0x71
> > [71813.679669] ? replay_one_buffer+0x53/0x53a [btrfs]
> > [71813.679669] replay_one_buffer+0x4a4/0x53a [btrfs]
> > [71813.679669] ? rcu_read_unlock+0x3a/0x57
> > [71813.679669] ? __lock_is_held+0x39/0x71
> > [71813.679669] walk_up_log_tree+0x101/0x1d2 [btrfs]
> > [71813.679669] walk_log_tree+0xad/0x188 [btrfs]
> > [71813.679669] btrfs_recover_log_trees+0x1fa/0x31e [btrfs]
> > [71813.679669] ? replay_one_extent+0x544/0x544 [btrfs]
> > [71813.679669] open_ctree+0x1cf6/0x2209 [btrfs]
> > [71813.679669] btrfs_mount_root+0x368/0x482 [btrfs]
> > [71813.679669] ? trace_hardirqs_on_caller+0x14c/0x1a6
> > [71813.679669] ? __lockdep_init_map+0x176/0x1c2
> > [71813.679669] ? mount_fs+0x64/0x10b
> > [71813.679669] mount_fs+0x64/0x10b
> > [71813.679669] vfs_kern_mount+0x68/0xce
> > [71813.679669] btrfs_mount+0x13e/0x772 [btrfs]
> > [71813.679669] ? trace_hardirqs_on_caller+0x14c/0x1a6
> > [71813.679669] ? __lockdep_init_map+0x176/0x1c2
> > [71813.679669] ? mount_fs+0x64/0x10b
> > [71813.679669] mount_fs+0x64/0x10b
> > [71813.679669] vfs_kern_mount+0x68/0xce
> > [71813.679669] do_mount+0x6e5/0x973
> > [71813.679669] ? memdup_user+0x3e/0x5c
> > [71813.679669] SyS_mount+0x72/0x98
> > [71813.679669] entry_SYSCALL_64_fastpath+0x1e/0x8b
> > [71813.679669] RIP: 0033:0x7f7cedf150ba
> > [71813.679669] RSP: 002b:00007ffca71da688 EFLAGS: 00000206
> > [71813.679669] Code: 7f a0 e8 51 0c fd ff 48 8b 43 50 f0 0f ba a8 30 2c
> > 00 00 02 72 17 41 83 fd fb 74 11 44 89 ee 48 c7 c7 7d 11 7f a0 e8 38 f5 8d
> > e0 <0f> ff 44 89 e9 ba 20 10 00 00 eb 4d 48 8b 4d b0 48 8b 75 88 4c
> > [71813.679669] ---[ end trace 83bd473fc5b4663b ]---
> > [71813.854764] BTRFS: error (device dm-0) in __btrfs_unlink_inode:4128:
> > errno=-2 No such entry
> > [71813.886994] BTRFS: error (device dm-0) in btrfs_replay_log:2307:
> > errno=-2 No such entry (Failed to recover log tree)
> > [71813.903357] BTRFS error (device dm-0): cleaner transaction attach
> > returned -30
> > [71814.128078] BTRFS error (device dm-0): open_ctree failed
> >
> > This happens because the log has inode reference items for both inode 258
> > (the first file we created) and inode 259 (the second file created), and
> > when processing the reference item for inode 258, we replace the
> > corresponding item in the subvolume tree (which has two names, "foo" and
> > "bar") witht he one in the log (which only has one name, "foo") without
> > removing the corresponding dir index keys from the parent directory.
> > Later, when processing the inode reference item for inode 259, which has
> > a name of "bar" associated to it, we notice that dir index entries exist
> > for that name and for a different inode, so we attempt to unlink that
> > name, which fails because the inode reference item for inode 258 no longer
> > has the name "bar" associated to it, making a call to btrfs_unlink_inode()
> > fail with a -ENOENT error.
> >
> > Fix this by unlinking all the names in an inode reference item from a
> > subvolume tree that are not present in the inode reference item found in
> > the log tree, before overwriting it with the item from the log tree.
>
> Since the order during replaying is INODE_ITEM then DIR_INDEX then
> other types, in this particular case, can we fix the problem by also
> logging the parent so that we have the correct DIR_INDEX?
>
> With DIR_INDEX, the problem would be fixed simpler, wouldn't it?
>
> Thanks,
>
> -liubo
> >
> > Signed-off-by: Filipe Manana <fdman...@suse.com>
> > ---
> > fs/btrfs/ctree.h | 5 ++-
> > fs/btrfs/inode-item.c | 44 ++++++++++++--------
> > fs/btrfs/tree-log.c | 112
> > ++++++++++++++++++++++++++++++++++++++++++++++++--
> > 3 files changed, 139 insertions(+), 22 deletions(-)
> >
> > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h
> > index 1a462ab85c49..5d33478bc704 100644
> > --- a/fs/btrfs/ctree.h
> > +++ b/fs/btrfs/ctree.h
> > @@ -3095,7 +3095,10 @@ btrfs_lookup_inode_extref(struct btrfs_trans_handle
> > *trans,
> > u64 inode_objectid, u64 ref_objectid, int ins_len,
> > int cow);
> >
> > -int btrfs_find_name_in_ext_backref(struct btrfs_path *path,
> > +int btrfs_find_name_in_backref(struct extent_buffer *leaf, int slot,
> > + const char *name,
> > + int name_len, struct btrfs_inode_ref **ref_ret);
> > +int btrfs_find_name_in_ext_backref(struct extent_buffer *leaf, int slot,
> > u64 ref_objectid, const char *name,
> > int name_len,
> > struct btrfs_inode_extref **extref_ret);
> > diff --git a/fs/btrfs/inode-item.c b/fs/btrfs/inode-item.c
> > index 39c968f80157..65e1a76bf755 100644
> > --- a/fs/btrfs/inode-item.c
> > +++ b/fs/btrfs/inode-item.c
> > @@ -22,10 +22,10 @@
> > #include "transaction.h"
> > #include "print-tree.h"
> >
> > -static int find_name_in_backref(struct btrfs_path *path, const char *name,
> > - int name_len, struct btrfs_inode_ref **ref_ret)
> > +int btrfs_find_name_in_backref(struct extent_buffer *leaf, int slot,
> > + const char *name,
> > + int name_len, struct btrfs_inode_ref **ref_ret)
> > {
> > - struct extent_buffer *leaf;
> > struct btrfs_inode_ref *ref;
> > unsigned long ptr;
> > unsigned long name_ptr;
> > @@ -33,9 +33,8 @@ static int find_name_in_backref(struct btrfs_path *path,
> > const char *name,
> > u32 cur_offset = 0;
> > int len;
> >
> > - leaf = path->nodes[0];
> > - item_size = btrfs_item_size_nr(leaf, path->slots[0]);
> > - ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
> > + item_size = btrfs_item_size_nr(leaf, slot);
> > + ptr = btrfs_item_ptr_offset(leaf, slot);
> > while (cur_offset < item_size) {
> > ref = (struct btrfs_inode_ref *)(ptr + cur_offset);
> > len = btrfs_inode_ref_name_len(leaf, ref);
> > @@ -44,18 +43,19 @@ static int find_name_in_backref(struct btrfs_path
> > *path, const char *name,
> > if (len != name_len)
> > continue;
> > if (memcmp_extent_buffer(leaf, name, name_ptr, name_len) == 0) {
> > - *ref_ret = ref;
> > + if (ref_ret)
> > + *ref_ret = ref;
> > return 1;
> > }
> > }
> > return 0;
> > }
> >
> > -int btrfs_find_name_in_ext_backref(struct btrfs_path *path, u64
> > ref_objectid,
> > +int btrfs_find_name_in_ext_backref(struct extent_buffer *leaf, int slot,
> > + u64 ref_objectid,
> > const char *name, int name_len,
> > struct btrfs_inode_extref **extref_ret)
> > {
> > - struct extent_buffer *leaf;
> > struct btrfs_inode_extref *extref;
> > unsigned long ptr;
> > unsigned long name_ptr;
> > @@ -63,9 +63,8 @@ int btrfs_find_name_in_ext_backref(struct btrfs_path
> > *path, u64 ref_objectid,
> > u32 cur_offset = 0;
> > int ref_name_len;
> >
> > - leaf = path->nodes[0];
> > - item_size = btrfs_item_size_nr(leaf, path->slots[0]);
> > - ptr = btrfs_item_ptr_offset(leaf, path->slots[0]);
> > + item_size = btrfs_item_size_nr(leaf, slot);
> > + ptr = btrfs_item_ptr_offset(leaf, slot);
> >
> > /*
> > * Search all extended backrefs in this item. We're only
> > @@ -113,7 +112,9 @@ btrfs_lookup_inode_extref(struct btrfs_trans_handle
> > *trans,
> > return ERR_PTR(ret);
> > if (ret > 0)
> > return NULL;
> > - if (!btrfs_find_name_in_ext_backref(path, ref_objectid, name, name_len,
> > &extref))
> > + if (!btrfs_find_name_in_ext_backref(path->nodes[0], path->slots[0],
> > + ref_objectid, name, name_len,
> > + &extref))
> > return NULL;
> > return extref;
> > }
> > @@ -155,7 +156,8 @@ static int btrfs_del_inode_extref(struct
> > btrfs_trans_handle *trans,
> > * This should always succeed so error here will make the FS
> > * readonly.
> > */
> > - if (!btrfs_find_name_in_ext_backref(path, ref_objectid,
> > + if (!btrfs_find_name_in_ext_backref(path->nodes[0], path->slots[0],
> > + ref_objectid,
> > name, name_len, &extref)) {
> > btrfs_handle_fs_error(root->fs_info, -ENOENT, NULL);
> > ret = -EROFS;
> > @@ -225,7 +227,8 @@ int btrfs_del_inode_ref(struct btrfs_trans_handle
> > *trans,
> > } else if (ret < 0) {
> > goto out;
> > }
> > - if (!find_name_in_backref(path, name, name_len, &ref)) {
> > + if (!btrfs_find_name_in_backref(path->nodes[0], path->slots[0],
> > + name, name_len, &ref)) {
> > ret = -ENOENT;
> > search_ext_refs = 1;
> > goto out;
> > @@ -293,7 +296,9 @@ static int btrfs_insert_inode_extref(struct
> > btrfs_trans_handle *trans,
> > ret = btrfs_insert_empty_item(trans, root, path, &key,
> > ins_len);
> > if (ret == -EEXIST) {
> > - if (btrfs_find_name_in_ext_backref(path, ref_objectid,
> > + if (btrfs_find_name_in_ext_backref(path->nodes[0],
> > + path->slots[0],
> > + ref_objectid,
> > name, name_len, NULL))
> > goto out;
> >
> > @@ -351,7 +356,8 @@ int btrfs_insert_inode_ref(struct btrfs_trans_handle
> > *trans,
> > if (ret == -EEXIST) {
> > u32 old_size;
> >
> > - if (find_name_in_backref(path, name, name_len, &ref))
> > + if (btrfs_find_name_in_backref(path->nodes[0], path->slots[0],
> > + name, name_len, &ref))
> > goto out;
> >
> > old_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
> > @@ -365,7 +371,9 @@ int btrfs_insert_inode_ref(struct btrfs_trans_handle
> > *trans,
> > ret = 0;
> > } else if (ret < 0) {
> > if (ret == -EOVERFLOW) {
> > - if (find_name_in_backref(path, name, name_len, &ref))
> > + if (btrfs_find_name_in_backref(path->nodes[0],
> > + path->slots[0],
> > + name, name_len, &ref))
> > ret = -EEXIST;
> > else
> > ret = -EMLINK;
> > diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
> > index 411a022489e4..fd573816f461 100644
> > --- a/fs/btrfs/tree-log.c
> > +++ b/fs/btrfs/tree-log.c
> > @@ -966,7 +966,9 @@ static noinline int backref_in_log(struct btrfs_root
> > *log,
> > ptr = btrfs_item_ptr_offset(path->nodes[0], path->slots[0]);
> >
> > if (key->type == BTRFS_INODE_EXTREF_KEY) {
> > - if (btrfs_find_name_in_ext_backref(path, ref_objectid,
> > + if (btrfs_find_name_in_ext_backref(path->nodes[0],
> > + path->slots[0],
> > + ref_objectid,
> > name, namelen, NULL))
> > match = 1;
> >
> > @@ -1190,7 +1192,8 @@ static int extref_get_fields(struct extent_buffer
> > *eb, unsigned long ref_ptr,
> > read_extent_buffer(eb, *name, (unsigned long)&extref->name,
> > *namelen);
> >
> > - *index = btrfs_inode_extref_index(eb, extref);
> > + if (index)
> > + *index = btrfs_inode_extref_index(eb, extref);
> > if (parent_objectid)
> > *parent_objectid = btrfs_inode_extref_parent(eb, extref);
> >
> > @@ -1211,12 +1214,102 @@ static int ref_get_fields(struct extent_buffer
> > *eb, unsigned long ref_ptr,
> >
> > read_extent_buffer(eb, *name, (unsigned long)(ref + 1), *namelen);
> >
> > - *index = btrfs_inode_ref_index(eb, ref);
> > + if (index)
> > + *index = btrfs_inode_ref_index(eb, ref);
> >
> > return 0;
> > }
> >
> > /*
> > + * Take an inode reference item from the log tree and iterate all names
> > from the
> > + * inode reference item in the subvolume tree with the same key (if it
> > exists).
> > + * For any name that is not in the inode reference item from the log tree,
> > do a
> > + * proper unlink of that name (that is, remove its entry from the inode
> > + * reference item and both dir index keys).
> > + */
> > +static int unlink_old_inode_refs(struct btrfs_trans_handle *trans,
> > + struct btrfs_root *root,
> > + struct btrfs_path *path,
> > + struct btrfs_inode *inode,
> > + struct extent_buffer *log_eb,
> > + int log_slot,
> > + struct btrfs_key *key)
> > +{
> > + int ret;
> > + unsigned long ref_ptr;
> > + unsigned long ref_end;
> > + struct extent_buffer *eb;
> > +
> > +again:
> > + btrfs_release_path(path);
> > + ret = btrfs_search_slot(NULL, root, key, path, 0, 0);
> > + if (ret > 0) {
> > + ret = 0;
> > + goto out;
> > + }
> > + if (ret < 0)
> > + goto out;
> > +
> > + eb = path->nodes[0];
> > + ref_ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
> > + ref_end = ref_ptr + btrfs_item_size_nr(eb, path->slots[0]);
> > + while (ref_ptr < ref_end) {
> > + char *name = NULL;
> > + int namelen;
> > + u64 parent_id;
> > +
> > + if (key->type == BTRFS_INODE_EXTREF_KEY) {
> > + ret = extref_get_fields(eb, ref_ptr, &namelen, &name,
> > + NULL, &parent_id);
> > + } else {
> > + parent_id = key->offset;
> > + ret = ref_get_fields(eb, ref_ptr, &namelen, &name,
> > + NULL);
> > + }
> > + if (ret)
> > + goto out;
> > +
> > + if (key->type == BTRFS_INODE_EXTREF_KEY)
> > + ret = btrfs_find_name_in_ext_backref(log_eb, log_slot,
> > + parent_id, name,
> > + namelen, NULL);
> > + else
> > + ret = btrfs_find_name_in_backref(log_eb, log_slot, name,
> > + namelen, NULL);
> > +
> > + if (!ret) {
> > + struct inode *dir;
> > +
> > + btrfs_release_path(path);
> > + dir = read_one_inode(root, parent_id);
> > + if (!dir) {
> > + ret = -ENOENT;
> > + kfree(name);
> > + goto out;
> > + }
> > + ret = btrfs_unlink_inode(trans, root, BTRFS_I(dir),
> > + inode, name, namelen);
> > + kfree(name);
> > + iput(dir);
> > + if (ret)
> > + goto out;
> > + goto again;
> > + }
> > +
> > + kfree(name);
> > + ref_ptr += namelen;
> > + if (key->type == BTRFS_INODE_EXTREF_KEY)
> > + ref_ptr += sizeof(struct btrfs_inode_extref);
> > + else
> > + ref_ptr += sizeof(struct btrfs_inode_ref);
> > + }
> > + ret = 0;
> > + out:
> > + btrfs_release_path(path);
> > + return ret;
> > +}
> > +
> > +/*
> > * replay one inode back reference item found in the log tree.
> > * eb, slot and key refer to the buffer and key found in the log tree.
> > * root is the destination we are replaying into, and path is for temp
> > @@ -1344,6 +1437,19 @@ static noinline int add_inode_ref(struct
> > btrfs_trans_handle *trans,
> > }
> > }
> >
> > + /*
> > + * Before we overwrite the inode reference item in the subvolume tree
> > + * with the item from the log tree, we must unlink all names from the
> > + * parent directory that are in the subvolume's tree inode reference
> > + * item, otherwise we end up with an inconsistent subvolume tree where
> > + * dir index entries exist for a name but there is no inode reference
> > + * item with the same name.
> > + */
> > + ret = unlink_old_inode_refs(trans, root, path, BTRFS_I(inode), eb, slot,
> > + key);
> > + if (ret)
> > + goto out;
> > +
> > /* finally write the back reference in the inode */
> > ret = overwrite_item(trans, root, path, eb, slot, key);
> > out:
> > --
> > 2.11.0
> >
> > --
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