Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs

Pull btrfs fixes from Chris Mason:
 "These are assorted fixes, mostly from Josef nailing down xfstests
  runs.  Zach also has a long standing fix for problems with readdir
  wrapping f_pos (or ctx->pos)

  These patches were spread out over different bases, so I rebased
  things on top of rc4 and retested overnight"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
  btrfs: don't loop on large offsets in readdir
  Btrfs: check to see if root_list is empty before adding it to dead roots
  Btrfs: release both paths before logging dir/changed extents
  Btrfs: allow splitting of hole em's when dropping extent cache
  Btrfs: make sure the backref walker catches all refs to our extent
  Btrfs: fix backref walking when we hit a compressed extent
  Btrfs: do not offset physical if we're compressed
  Btrfs: fix extent buffer leak after backref walking
  Btrfs: fix a bug of snapshot-aware defrag to make it work on partial extents
  btrfs: fix file truncation if FALLOC_FL_KEEP_SIZE is specified

8 files changed, 119 insertions, 68 deletions

diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index eaf133384a8f..8bc5e8ccb091 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -36,16 +36,23 @@ static int check_extent_in_eb(struct btrfs_key *key, struct extent_buffer *eb,
                                 u64 extent_item_pos,
                                 struct extent_inode_elem **eie)
 {
-        u64 data_offset;
-        u64 data_len;
+        u64 offset = 0;
         struct extent_inode_elem *e;
 
-        data_offset = btrfs_file_extent_offset(eb, fi);
-        data_len = btrfs_file_extent_num_bytes(eb, fi);
+        if (!btrfs_file_extent_compression(eb, fi) &&
+            !btrfs_file_extent_encryption(eb, fi) &&
+            !btrfs_file_extent_other_encoding(eb, fi)) {
+                u64 data_offset;
+                u64 data_len;
 
-        if (extent_item_pos < data_offset ||
-            extent_item_pos >= data_offset + data_len)
-                return 1;
+                data_offset = btrfs_file_extent_offset(eb, fi);
+                data_len = btrfs_file_extent_num_bytes(eb, fi);
+
+                if (extent_item_pos < data_offset ||
+                    extent_item_pos >= data_offset + data_len)
+                        return 1;
+                offset = extent_item_pos - data_offset;
+        }
 
         e = kmalloc(sizeof(*e), GFP_NOFS);
         if (!e)
@@ -53,7 +60,7 @@ static int check_extent_in_eb(struct btrfs_key *key, struct extent_buffer *eb,
 
         e->next = *eie;
         e->inum = key->objectid;
-        e->offset = key->offset + (extent_item_pos - data_offset);
+        e->offset = key->offset + offset;
         *eie = e;
 
         return 0;
@@ -189,7 +196,7 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
         struct extent_buffer *eb;
         struct btrfs_key key;
         struct btrfs_file_extent_item *fi;
-        struct extent_inode_elem *eie = NULL;
+        struct extent_inode_elem *eie = NULL, *old = NULL;
         u64 disk_byte;
 
         if (level != 0) {
@@ -223,6 +230,7 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
 
                 if (disk_byte == wanted_disk_byte) {
                         eie = NULL;
+                        old = NULL;
                         if (extent_item_pos) {
                                 ret = check_extent_in_eb(&key, eb, fi,
                                                 *extent_item_pos,
@@ -230,18 +238,20 @@ static int add_all_parents(struct btrfs_root *root, struct btrfs_path *path,
                                 if (ret < 0)
                                         break;
                         }
-                        if (!ret) {
-                                ret = ulist_add(parents, eb->start,
-                                                (uintptr_t)eie, GFP_NOFS);
-                                if (ret < 0)
-                                        break;
-                                if (!extent_item_pos) {
-                                        ret = btrfs_next_old_leaf(root, path,
-                                                        time_seq);
-                                        continue;
-                                }
+                        if (ret > 0)
+                                goto next;
+                        ret = ulist_add_merge(parents, eb->start,
+                                              (uintptr_t)eie,
+                                              (u64 *)&old, GFP_NOFS);
+                        if (ret < 0)
+                                break;
+                        if (!ret && extent_item_pos) {
+                                while (old->next)
+                                        old = old->next;
+                                old->next = eie;
                         }
                 }
+next:
                 ret = btrfs_next_old_item(root, path, time_seq);
         }
 
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 5bf4c39e2ad6..ed504607d8ec 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -1271,7 +1271,6 @@ tree_mod_log_rewind(struct btrfs_fs_info *fs_info, struct extent_buffer *eb,
                 BUG_ON(!eb_rewin);
         }
 
-        extent_buffer_get(eb_rewin);
         btrfs_tree_read_unlock(eb);
         free_extent_buffer(eb);
 
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 583d98bd065e..fe443fece851 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -4048,7 +4048,7 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
         }
 
         while (!end) {
-                u64 offset_in_extent;
+                u64 offset_in_extent = 0;
 
                 /* break if the extent we found is outside the range */
                 if (em->start >= max || extent_map_end(em) < off)
@@ -4064,9 +4064,12 @@ int extent_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
 
                 /*
                  * record the offset from the start of the extent
-                 * for adjusting the disk offset below
+                 * for adjusting the disk offset below.  Only do this if the
+                 * extent isn't compressed since our in ram offset may be past
+                 * what we have actually allocated on disk.
                  */
-                offset_in_extent = em_start - em->start;
+                if (!test_bit(EXTENT_FLAG_COMPRESSED, &em->flags))
+                        offset_in_extent = em_start - em->start;
                 em_end = extent_map_end(em);
                 em_len = em_end - em_start;
                 emflags = em->flags;
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index a005fe2c072a..8e686a427ce2 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -596,20 +596,29 @@ void btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
                 if (no_splits)
                         goto next;
 
-                if (em->block_start < EXTENT_MAP_LAST_BYTE &&
-                    em->start < start) {
+                if (em->start < start) {
                         split->start = em->start;
                         split->len = start - em->start;
-                        split->orig_start = em->orig_start;
-                        split->block_start = em->block_start;
 
-                        if (compressed)
-                                split->block_len = em->block_len;
-                        else
-                                split->block_len = split->len;
-                        split->ram_bytes = em->ram_bytes;
-                        split->orig_block_len = max(split->block_len,
-                                                    em->orig_block_len);
+                        if (em->block_start < EXTENT_MAP_LAST_BYTE) {
+                                split->orig_start = em->orig_start;
+                                split->block_start = em->block_start;
+
+                                if (compressed)
+                                        split->block_len = em->block_len;
+                                else
+                                        split->block_len = split->len;
+                                split->orig_block_len = max(split->block_len,
+                                                em->orig_block_len);
+                                split->ram_bytes = em->ram_bytes;
+                        } else {
+                                split->orig_start = split->start;
+                                split->block_len = 0;
+                                split->block_start = em->block_start;
+                                split->orig_block_len = 0;
+                                split->ram_bytes = split->len;
+                        }
+
                         split->generation = gen;
                         split->bdev = em->bdev;
                         split->flags = flags;
@@ -620,8 +629,7 @@ void btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
                         split = split2;
                         split2 = NULL;
                 }
-                if (em->block_start < EXTENT_MAP_LAST_BYTE &&
-                    testend && em->start + em->len > start + len) {
+                if (testend && em->start + em->len > start + len) {
                         u64 diff = start + len - em->start;
 
                         split->start = start + len;
@@ -630,18 +638,28 @@ void btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
                         split->flags = flags;
                         split->compress_type = em->compress_type;
                         split->generation = gen;
-                        split->orig_block_len = max(em->block_len,
+
+                        if (em->block_start < EXTENT_MAP_LAST_BYTE) {
+                                split->orig_block_len = max(em->block_len,
                                                     em->orig_block_len);
-                        split->ram_bytes = em->ram_bytes;
 
-                        if (compressed) {
-                                split->block_len = em->block_len;
-                                split->block_start = em->block_start;
-                                split->orig_start = em->orig_start;
+                                split->ram_bytes = em->ram_bytes;
+                                if (compressed) {
+                                        split->block_len = em->block_len;
+                                        split->block_start = em->block_start;
+                                        split->orig_start = em->orig_start;
+                                } else {
+                                        split->block_len = split->len;
+                                        split->block_start = em->block_start
+                                                + diff;
+                                        split->orig_start = em->orig_start;
+                                }
                         } else {
-                                split->block_len = split->len;
-                                split->block_start = em->block_start + diff;
-                                split->orig_start = em->orig_start;
+                                split->ram_bytes = split->len;
+                                split->orig_start = split->start;
+                                split->block_len = 0;
+                                split->block_start = em->block_start;
+                                split->orig_block_len = 0;
                         }
 
                         ret = add_extent_mapping(em_tree, split, modified);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 6d1b93c8aafb..021694c08181 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2166,16 +2166,23 @@ static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
                 if (btrfs_file_extent_disk_bytenr(leaf, extent) != old->bytenr)
                         continue;
 
-                extent_offset = btrfs_file_extent_offset(leaf, extent);
-                if (key.offset - extent_offset != offset)
+                /*
+                 * 'offset' refers to the exact key.offset,
+                 * NOT the 'offset' field in btrfs_extent_data_ref, ie.
+                 * (key.offset - extent_offset).
+                 */
+                if (key.offset != offset)
                         continue;
 
+                extent_offset = btrfs_file_extent_offset(leaf, extent);
                 num_bytes = btrfs_file_extent_num_bytes(leaf, extent);
+
                 if (extent_offset >= old->extent_offset + old->offset +
                     old->len || extent_offset + num_bytes <=
                     old->extent_offset + old->offset)
                         continue;
 
+                ret = 0;
                 break;
         }
 
@@ -2187,7 +2194,7 @@ static noinline int record_one_backref(u64 inum, u64 offset, u64 root_id,
 
         backref->root_id = root_id;
         backref->inum = inum;
-        backref->file_pos = offset + extent_offset;
+        backref->file_pos = offset;
         backref->num_bytes = num_bytes;
         backref->extent_offset = extent_offset;
         backref->generation = btrfs_file_extent_generation(leaf, extent);
@@ -2210,7 +2217,8 @@ static noinline bool record_extent_backrefs(struct btrfs_path *path,
         new->path = path;
 
         list_for_each_entry_safe(old, tmp, &new->head, list) {
-                ret = iterate_inodes_from_logical(old->bytenr, fs_info,
+                ret = iterate_inodes_from_logical(old->bytenr +
+                                                  old->extent_offset, fs_info,
                                                   path, record_one_backref,
                                                   old);
                 BUG_ON(ret < 0 && ret != -ENOENT);
@@ -4391,9 +4399,6 @@ static int btrfs_setsize(struct inode *inode, struct iattr *attr)
         int mask = attr->ia_valid;
         int ret;
 
-        if (newsize == oldsize)
-                return 0;
-
         /*
          * The regular truncate() case without ATTR_CTIME and ATTR_MTIME is a
          * special case where we need to update the times despite not having
@@ -5165,14 +5170,31 @@ next:
         }
 
         /* Reached end of directory/root. Bump pos past the last item. */
-        if (key_type == BTRFS_DIR_INDEX_KEY)
-                /*
-                 * 32-bit glibc will use getdents64, but then strtol -
-                 * so the last number we can serve is this.
-                 */
-                ctx->pos = 0x7fffffff;
-        else
-                ctx->pos++;
+        ctx->pos++;
+
+        /*
+         * Stop new entries from being returned after we return the last
+         * entry.
+         *
+         * New directory entries are assigned a strictly increasing
+         * offset.  This means that new entries created during readdir
+         * are *guaranteed* to be seen in the future by that readdir.
+         * This has broken buggy programs which operate on names as
+         * they're returned by readdir.  Until we re-use freed offsets
+         * we have this hack to stop new entries from being returned
+         * under the assumption that they'll never reach this huge
+         * offset.
+         *
+         * This is being careful not to overflow 32bit loff_t unless the
+         * last entry requires it because doing so has broken 32bit apps
+         * in the past.
+         */
+        if (key_type == BTRFS_DIR_INDEX_KEY) {
+                if (ctx->pos >= INT_MAX)
+                        ctx->pos = LLONG_MAX;
+                else
+                        ctx->pos = INT_MAX;
+        }
 nopos:
         ret = 0;
 err:
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index d58cce77fc6c..af1931a5960d 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -983,12 +983,12 @@ static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
  * a dirty root struct and adds it into the list of dead roots that need to
  * be deleted
  */
-int btrfs_add_dead_root(struct btrfs_root *root)
+void btrfs_add_dead_root(struct btrfs_root *root)
 {
         spin_lock(&root->fs_info->trans_lock);
-        list_add_tail(&root->root_list, &root->fs_info->dead_roots);
+        if (list_empty(&root->root_list))
+                list_add_tail(&root->root_list, &root->fs_info->dead_roots);
         spin_unlock(&root->fs_info->trans_lock);
-        return 0;
 }
 
 /*
@@ -1925,7 +1925,7 @@ int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root)
         }
         root = list_first_entry(&fs_info->dead_roots,
                         struct btrfs_root, root_list);
-        list_del(&root->root_list);
+        list_del_init(&root->root_list);
         spin_unlock(&fs_info->trans_lock);
 
         pr_debug("btrfs: cleaner removing %llu\n",
diff --git a/fs/btrfs/transaction.h b/fs/btrfs/transaction.h
index 005b0375d18c..defbc4269897 100644
--- a/fs/btrfs/transaction.h
+++ b/fs/btrfs/transaction.h
@@ -143,7 +143,7 @@ int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid);
 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
                                      struct btrfs_root *root);
 
-int btrfs_add_dead_root(struct btrfs_root *root);
+void btrfs_add_dead_root(struct btrfs_root *root);
 int btrfs_defrag_root(struct btrfs_root *root);
 int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root);
 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c
index 2c6791493637..ff60d8978ae2 100644
--- a/fs/btrfs/tree-log.c
+++ b/fs/btrfs/tree-log.c
@@ -3746,8 +3746,9 @@ next_slot:
         }
 
 log_extents:
+        btrfs_release_path(path);
+        btrfs_release_path(dst_path);
         if (fast_search) {
-                btrfs_release_path(dst_path);
                 ret = btrfs_log_changed_extents(trans, root, inode, dst_path);
                 if (ret) {
                         err = ret;
@@ -3764,8 +3765,6 @@ log_extents:
         }
 
         if (inode_only == LOG_INODE_ALL && S_ISDIR(inode->i_mode)) {
-                btrfs_release_path(path);
-                btrfs_release_path(dst_path);
                 ret = log_directory_changes(trans, root, inode, path, dst_path);
                 if (ret) {
                         err = ret;