[PATCH 2/4] btrfs-progs: Simplify memory allocation for enumerate_dead_subvols

[Zhao Lei]

No need prepare memory for enumerate_dead_subvols() in caller, and pass
additional argument for allocated length.

Just do every thing inside enumerate_dead_subvols(), it will not
increase malloc count, but make code simple.

Signed-off-by: Zhao Lei <zhao...@cn.fujitsu.com>
---
 cmds-subvolume.c | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/cmds-subvolume.c b/cmds-subvolume.c
index 8e8d019..0d83bd5 100644
--- a/cmds-subvolume.c
+++ b/cmds-subvolume.c
@@ -1169,12 +1169,13 @@ again:
  * Enumerate all dead subvolumes that exist in the filesystem.
  * Fill @ids and reallocate to bigger size if needed.
  */
-static int enumerate_dead_subvols(int fd, int count, u64 **ids)
+static int enumerate_dead_subvols(int fd, u64 **ids)
 {
        int ret;
        struct btrfs_ioctl_search_args args;
        struct btrfs_ioctl_search_key *sk = &args.key;
        int idx = 0;
+       int count = 0;
 
        memset(&args, 0, sizeof(args));
 
@@ -1189,6 +1190,7 @@ static int enumerate_dead_subvols(int fd, int count, u64 
**ids)
        sk->max_transid = (u64)-1;
        sk->nr_items = 4096;
 
+       *ids = NULL;
        while (1) {
                struct btrfs_ioctl_search_header *sh;
                unsigned long off;
@@ -1207,8 +1209,6 @@ static int enumerate_dead_subvols(int fd, int count, u64 
**ids)
                        off += sizeof(*sh);
 
                        if (sh->type == BTRFS_ORPHAN_ITEM_KEY) {
-                               (*ids)[idx] = sh->offset;
-                               idx++;
                                if (idx >= count) {
                                        u64 *newids;
 
@@ -1218,6 +1218,8 @@ static int enumerate_dead_subvols(int fd, int count, u64 
**ids)
                                                return -ENOMEM;
                                        *ids = newids;
                                }
+                               (*ids)[idx] = sh->offset;
+                               idx++;
                        }
                        off += sh->len;
 
@@ -1284,14 +1286,7 @@ static int cmd_subvol_sync(int argc, char **argv)
 
        id_count = argc - optind;
        if (!id_count) {
-               id_count = SUBVOL_ID_BATCH;
-               ids = (u64*)malloc(id_count * sizeof(u64));
-               if (!ids) {
-                       fprintf(stderr, "ERROR: not enough memory\n");
-                       ret = 1;
-                       goto out;
-               }
-               id_count = enumerate_dead_subvols(fd, id_count, &ids);
+               id_count = enumerate_dead_subvols(fd, &ids);
                if (id_count < 0) {
                        fprintf(stderr, "ERROR: can't enumerate dead 
subvolumes: %s\n",
                                        strerror(-id_count));
-- 
1.8.5.1

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