xiaomi-sm8450/android_kernel_xiaomi_sm8450
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btrfs: kill the subvol_srcu

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Now that we have proper root ref counting everywhere we can kill the
subvol_srcu.

* removal of fs_info::subvol_srcu reduces size of fs_info by 1176 bytes

* the refcount_t used for the references checks for accidental 0->1
  in cases where the root lifetime would not be properly protected

* there's a leak detector for roots to catch unfreed roots at umount
  time

* SRCU served us well over the years but is was not a proper
  synchronization mechanism for some cases

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ update changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Josef Bacik
2020-02-14 16:11:47 -05:00
committed by David Sterba
parent efc3453494
commit c75e839414
8 changed files with 14 additions and 88 deletions
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3
fs/btrfs/inode.c
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@@ -5364,7 +5364,6 @@ struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
struct btrfs_root *sub_root = root;
struct btrfs_key location;
u8 di_type = 0;
int index;
int ret = 0;
if (dentry->d_name.len > BTRFS_NAME_LEN)
@@ -5391,7 +5390,6 @@ struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
return inode;
}
index = srcu_read_lock(&fs_info->subvol_srcu);
ret = fixup_tree_root_location(fs_info, dir, dentry,
&location, &sub_root);
if (ret < 0) {
@@ -5404,7 +5402,6 @@ struct inode *btrfs_lookup_dentry(struct inode *dir, struct dentry *dentry)
}
if (root != sub_root)
btrfs_put_root(sub_root);
srcu_read_unlock(&fs_info->subvol_srcu, index);
if (!IS_ERR(inode) && root != sub_root) {
down_read(&fs_info->cleanup_work_sem);