From: Filipe Manana <fdmanana@xxxxxxxx> commit 0b3f407e6728d990ae1630a02c7b952c21c288d3 upstream. When doing an incremental send, if we have a new inode that happens to have the same number that an old directory inode had in the base snapshot and that old directory has a pending rmdir operation, we end up computing a wrong path for the new inode, causing the receiver to fail. Example reproducer: $ cat test-send-rmdir.sh #!/bin/bash DEV=/dev/sdi MNT=/mnt/sdi mkfs.btrfs -f $DEV >/dev/null mount $DEV $MNT mkdir $MNT/dir touch $MNT/dir/file1 touch $MNT/dir/file2 touch $MNT/dir/file3 # Filesystem looks like: # # . (ino 256) # |----- dir/ (ino 257) # |----- file1 (ino 258) # |----- file2 (ino 259) # |----- file3 (ino 260) # btrfs subvolume snapshot -r $MNT $MNT/snap1 btrfs send -f /tmp/snap1.send $MNT/snap1 # Now remove our directory and all its files. rm -fr $MNT/dir # Unmount the filesystem and mount it again. This is to ensure that # the next inode that is created ends up with the same inode number # that our directory "dir" had, 257, which is the first free "objectid" # available after mounting again the filesystem. umount $MNT mount $DEV $MNT # Now create a new file (it could be a directory as well). touch $MNT/newfile # Filesystem now looks like: # # . (ino 256) # |----- newfile (ino 257) # btrfs subvolume snapshot -r $MNT $MNT/snap2 btrfs send -f /tmp/snap2.send -p $MNT/snap1 $MNT/snap2 # Now unmount the filesystem, create a new one, mount it and try to apply # both send streams to recreate both snapshots. umount $DEV mkfs.btrfs -f $DEV >/dev/null mount $DEV $MNT btrfs receive -f /tmp/snap1.send $MNT btrfs receive -f /tmp/snap2.send $MNT umount $MNT When running the test, the receive operation for the incremental stream fails: $ ./test-send-rmdir.sh Create a readonly snapshot of '/mnt/sdi' in '/mnt/sdi/snap1' At subvol /mnt/sdi/snap1 Create a readonly snapshot of '/mnt/sdi' in '/mnt/sdi/snap2' At subvol /mnt/sdi/snap2 At subvol snap1 At snapshot snap2 ERROR: chown o257-9-0 failed: No such file or directory So fix this by tracking directories that have a pending rmdir by inode number and generation number, instead of only inode number. A test case for fstests follows soon. Reported-by: Massimo B. <massimo.b@xxxxxxx> Tested-by: Massimo B. <massimo.b@xxxxxxx> Link: https://lore.kernel.org/linux-btrfs/6ae34776e85912960a253a8327068a892998e685.camel@xxxxxxx/ CC: stable@xxxxxxxxxxxxxxx # 4.19+ Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx> Signed-off-by: David Sterba <dsterba@xxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/btrfs/send.c | 49 +++++++++++++++++++++++++++++++------------------ 1 file changed, 31 insertions(+), 18 deletions(-) --- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -238,6 +238,7 @@ struct waiting_dir_move { * after this directory is moved, we can try to rmdir the ino rmdir_ino. */ u64 rmdir_ino; + u64 rmdir_gen; bool orphanized; }; @@ -308,7 +309,7 @@ static int is_waiting_for_move(struct se static struct waiting_dir_move * get_waiting_dir_move(struct send_ctx *sctx, u64 ino); -static int is_waiting_for_rm(struct send_ctx *sctx, u64 dir_ino); +static int is_waiting_for_rm(struct send_ctx *sctx, u64 dir_ino, u64 gen); static int need_send_hole(struct send_ctx *sctx) { @@ -2304,7 +2305,7 @@ static int get_cur_path(struct send_ctx fs_path_reset(name); - if (is_waiting_for_rm(sctx, ino)) { + if (is_waiting_for_rm(sctx, ino, gen)) { ret = gen_unique_name(sctx, ino, gen, name); if (ret < 0) goto out; @@ -2863,8 +2864,8 @@ out: return ret; } -static struct orphan_dir_info * -add_orphan_dir_info(struct send_ctx *sctx, u64 dir_ino) +static struct orphan_dir_info *add_orphan_dir_info(struct send_ctx *sctx, + u64 dir_ino, u64 dir_gen) { struct rb_node **p = &sctx->orphan_dirs.rb_node; struct rb_node *parent = NULL; @@ -2873,20 +2874,23 @@ add_orphan_dir_info(struct send_ctx *sct while (*p) { parent = *p; entry = rb_entry(parent, struct orphan_dir_info, node); - if (dir_ino < entry->ino) { + if (dir_ino < entry->ino) p = &(*p)->rb_left; - } else if (dir_ino > entry->ino) { + else if (dir_ino > entry->ino) p = &(*p)->rb_right; - } else { + else if (dir_gen < entry->gen) + p = &(*p)->rb_left; + else if (dir_gen > entry->gen) + p = &(*p)->rb_right; + else return entry; - } } odi = kmalloc(sizeof(*odi), GFP_KERNEL); if (!odi) return ERR_PTR(-ENOMEM); odi->ino = dir_ino; - odi->gen = 0; + odi->gen = dir_gen; odi->last_dir_index_offset = 0; rb_link_node(&odi->node, parent, p); @@ -2894,8 +2898,8 @@ add_orphan_dir_info(struct send_ctx *sct return odi; } -static struct orphan_dir_info * -get_orphan_dir_info(struct send_ctx *sctx, u64 dir_ino) +static struct orphan_dir_info *get_orphan_dir_info(struct send_ctx *sctx, + u64 dir_ino, u64 gen) { struct rb_node *n = sctx->orphan_dirs.rb_node; struct orphan_dir_info *entry; @@ -2906,15 +2910,19 @@ get_orphan_dir_info(struct send_ctx *sct n = n->rb_left; else if (dir_ino > entry->ino) n = n->rb_right; + else if (gen < entry->gen) + n = n->rb_left; + else if (gen > entry->gen) + n = n->rb_right; else return entry; } return NULL; } -static int is_waiting_for_rm(struct send_ctx *sctx, u64 dir_ino) +static int is_waiting_for_rm(struct send_ctx *sctx, u64 dir_ino, u64 gen) { - struct orphan_dir_info *odi = get_orphan_dir_info(sctx, dir_ino); + struct orphan_dir_info *odi = get_orphan_dir_info(sctx, dir_ino, gen); return odi != NULL; } @@ -2959,7 +2967,7 @@ static int can_rmdir(struct send_ctx *sc key.type = BTRFS_DIR_INDEX_KEY; key.offset = 0; - odi = get_orphan_dir_info(sctx, dir); + odi = get_orphan_dir_info(sctx, dir, dir_gen); if (odi) key.offset = odi->last_dir_index_offset; @@ -2990,7 +2998,7 @@ static int can_rmdir(struct send_ctx *sc dm = get_waiting_dir_move(sctx, loc.objectid); if (dm) { - odi = add_orphan_dir_info(sctx, dir); + odi = add_orphan_dir_info(sctx, dir, dir_gen); if (IS_ERR(odi)) { ret = PTR_ERR(odi); goto out; @@ -2998,12 +3006,13 @@ static int can_rmdir(struct send_ctx *sc odi->gen = dir_gen; odi->last_dir_index_offset = found_key.offset; dm->rmdir_ino = dir; + dm->rmdir_gen = dir_gen; ret = 0; goto out; } if (loc.objectid > send_progress) { - odi = add_orphan_dir_info(sctx, dir); + odi = add_orphan_dir_info(sctx, dir, dir_gen); if (IS_ERR(odi)) { ret = PTR_ERR(odi); goto out; @@ -3043,6 +3052,7 @@ static int add_waiting_dir_move(struct s return -ENOMEM; dm->ino = ino; dm->rmdir_ino = 0; + dm->rmdir_gen = 0; dm->orphanized = orphanized; while (*p) { @@ -3188,7 +3198,7 @@ static int path_loop(struct send_ctx *sc while (ino != BTRFS_FIRST_FREE_OBJECTID) { fs_path_reset(name); - if (is_waiting_for_rm(sctx, ino)) + if (is_waiting_for_rm(sctx, ino, gen)) break; if (is_waiting_for_move(sctx, ino)) { if (*ancestor_ino == 0) @@ -3228,6 +3238,7 @@ static int apply_dir_move(struct send_ct u64 parent_ino, parent_gen; struct waiting_dir_move *dm = NULL; u64 rmdir_ino = 0; + u64 rmdir_gen; u64 ancestor; bool is_orphan; int ret; @@ -3242,6 +3253,7 @@ static int apply_dir_move(struct send_ct dm = get_waiting_dir_move(sctx, pm->ino); ASSERT(dm); rmdir_ino = dm->rmdir_ino; + rmdir_gen = dm->rmdir_gen; is_orphan = dm->orphanized; free_waiting_dir_move(sctx, dm); @@ -3278,6 +3290,7 @@ static int apply_dir_move(struct send_ct dm = get_waiting_dir_move(sctx, pm->ino); ASSERT(dm); dm->rmdir_ino = rmdir_ino; + dm->rmdir_gen = rmdir_gen; } goto out; } @@ -3296,7 +3309,7 @@ static int apply_dir_move(struct send_ct struct orphan_dir_info *odi; u64 gen; - odi = get_orphan_dir_info(sctx, rmdir_ino); + odi = get_orphan_dir_info(sctx, rmdir_ino, rmdir_gen); if (!odi) { /* already deleted */ goto finish;
