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authorJosef Bacik <josef@redhat.com>2010-11-19 14:59:15 -0500
committerChris Mason <chris.mason@oracle.com>2010-11-27 13:37:51 -0500
commit450ba0ea06b6ed3612d27f2b7127a9de4160f285 (patch)
tree2276ddbcb65d7656416cdce69432a5858b35c413
parent975f84fee2e8a77ee5f41bfe7c5682bf29366b10 (diff)
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Btrfs: setup blank root and fs_info for mount time
There is a problem with how we use sget, it searches through the list of supers attached to the fs_type looking for a super with the same fs_devices as what we're trying to mount. This depends on sb->s_fs_info being filled, but we don't fill that in until we get to btrfs_fill_super, so we could hit supers on the fs_type super list that have a null s_fs_info. In order to fix that we need to go ahead and setup a blank root with a blank fs_info to hold fs_devices, that way our test will work out right and then we can set s_fs_info in btrfs_set_super, and then open_ctree will simply use our pre-allocated root and fs_info when setting everything up. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
-rw-r--r--fs/btrfs/disk-io.c6
-rw-r--r--fs/btrfs/super.c34
2 files changed, 33 insertions, 7 deletions
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index a67b98d58c2..57c9d8eeb7d 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1561,10 +1561,8 @@ struct btrfs_root *open_ctree(struct super_block *sb,
GFP_NOFS);
struct btrfs_root *csum_root = kzalloc(sizeof(struct btrfs_root),
GFP_NOFS);
- struct btrfs_root *tree_root = kzalloc(sizeof(struct btrfs_root),
- GFP_NOFS);
- struct btrfs_fs_info *fs_info = kzalloc(sizeof(*fs_info),
- GFP_NOFS);
+ struct btrfs_root *tree_root = btrfs_sb(sb);
+ struct btrfs_fs_info *fs_info = tree_root->fs_info;
struct btrfs_root *chunk_root = kzalloc(sizeof(struct btrfs_root),
GFP_NOFS);
struct btrfs_root *dev_root = kzalloc(sizeof(struct btrfs_root),
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 141fb317d3b..47bf67cbe6b 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -563,7 +563,7 @@ static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
static int btrfs_test_super(struct super_block *s, void *data)
{
- struct btrfs_fs_devices *test_fs_devices = data;
+ struct btrfs_root *test_root = data;
struct btrfs_root *root = btrfs_sb(s);
/*
@@ -572,9 +572,17 @@ static int btrfs_test_super(struct super_block *s, void *data)
*/
if (!atomic_read(&s->s_active))
return 0;
- return root->fs_info->fs_devices == test_fs_devices;
+ return root->fs_info->fs_devices == test_root->fs_info->fs_devices;
}
+static int btrfs_set_super(struct super_block *s, void *data)
+{
+ s->s_fs_info = data;
+
+ return set_anon_super(s, data);
+}
+
+
/*
* Find a superblock for the given device / mount point.
*
@@ -588,6 +596,8 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags,
struct super_block *s;
struct dentry *root;
struct btrfs_fs_devices *fs_devices = NULL;
+ struct btrfs_root *tree_root = NULL;
+ struct btrfs_fs_info *fs_info = NULL;
fmode_t mode = FMODE_READ;
char *subvol_name = NULL;
u64 subvol_objectid = 0;
@@ -615,8 +625,24 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags,
goto error_close_devices;
}
+ /*
+ * Setup a dummy root and fs_info for test/set super. This is because
+ * we don't actually fill this stuff out until open_ctree, but we need
+ * it for searching for existing supers, so this lets us do that and
+ * then open_ctree will properly initialize everything later.
+ */
+ fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
+ tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
+ if (!fs_info || !tree_root) {
+ error = -ENOMEM;
+ goto error_close_devices;
+ }
+ fs_info->tree_root = tree_root;
+ fs_info->fs_devices = fs_devices;
+ tree_root->fs_info = fs_info;
+
bdev = fs_devices->latest_bdev;
- s = sget(fs_type, btrfs_test_super, set_anon_super, fs_devices);
+ s = sget(fs_type, btrfs_test_super, btrfs_set_super, tree_root);
if (IS_ERR(s))
goto error_s;
@@ -685,6 +711,8 @@ error_s:
error = PTR_ERR(s);
error_close_devices:
btrfs_close_devices(fs_devices);
+ kfree(fs_info);
+ kfree(tree_root);
error_free_subvol_name:
kfree(subvol_name);
return error;