119 lines
4.2 KiB
Diff
119 lines
4.2 KiB
Diff
From 7f9f05e1f4cd9a625bc35b117a239d9b0cbe4a03 Mon Sep 17 00:00:00 2001
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From: Josef Bacik <josef@redhat.com>
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Date: Fri, 19 Nov 2010 14:59:15 -0500
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Subject: [PATCH 3/3] Btrfs: setup blank root and fs_info for mount time
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There is a problem with how we use sget, it searches through the list of supers
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attached to the fs_type looking for a super with the same fs_devices as what
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we're trying to mount. This depends on sb->s_fs_info being filled, but we don't
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fill that in until we get to btrfs_fill_super, so we could hit supers on the
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fs_type super list that have a null s_fs_info. In order to fix that we need to
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go ahead and setup a blank root with a blank fs_info to hold fs_devices, that
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way our test will work out right and then we can set s_fs_info in
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btrfs_set_super, and then open_ctree will simply use our pre-allocated root and
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fs_info when setting everything up. Thanks,
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Signed-off-by: Josef Bacik <josef@redhat.com>
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Signed-off-by: Chris Mason <chris.mason@oracle.com>
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---
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fs/btrfs/disk-io.c | 6 ++----
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fs/btrfs/super.c | 34 +++++++++++++++++++++++++++++++---
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2 files changed, 33 insertions(+), 7 deletions(-)
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diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
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index 64f1008..65efa04 100644
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--- a/fs/btrfs/disk-io.c
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+++ b/fs/btrfs/disk-io.c
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@@ -1539,10 +1539,8 @@ struct btrfs_root *open_ctree(struct super_block *sb,
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GFP_NOFS);
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struct btrfs_root *csum_root = kzalloc(sizeof(struct btrfs_root),
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GFP_NOFS);
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- struct btrfs_root *tree_root = kzalloc(sizeof(struct btrfs_root),
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- GFP_NOFS);
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- struct btrfs_fs_info *fs_info = kzalloc(sizeof(*fs_info),
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- GFP_NOFS);
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+ struct btrfs_root *tree_root = btrfs_sb(sb);
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+ struct btrfs_fs_info *fs_info = tree_root->fs_info;
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struct btrfs_root *chunk_root = kzalloc(sizeof(struct btrfs_root),
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GFP_NOFS);
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struct btrfs_root *dev_root = kzalloc(sizeof(struct btrfs_root),
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diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
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index b169698..6479db9 100644
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--- a/fs/btrfs/super.c
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+++ b/fs/btrfs/super.c
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@@ -548,7 +548,7 @@ static int btrfs_show_options(struct seq_file *seq, struct vfsmount *vfs)
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static int btrfs_test_super(struct super_block *s, void *data)
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{
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- struct btrfs_fs_devices *test_fs_devices = data;
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+ struct btrfs_root *test_root = data;
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struct btrfs_root *root = btrfs_sb(s);
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/*
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@@ -557,9 +557,17 @@ static int btrfs_test_super(struct super_block *s, void *data)
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*/
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if (!atomic_read(&s->s_active))
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return 0;
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- return root->fs_info->fs_devices == test_fs_devices;
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+ return root->fs_info->fs_devices == test_root->fs_info->fs_devices;
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}
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+static int btrfs_set_super(struct super_block *s, void *data)
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+{
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+ s->s_fs_info = data;
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+
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+ return set_anon_super(s, data);
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+}
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+
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+
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/*
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* Find a superblock for the given device / mount point.
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*
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@@ -573,6 +581,8 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags,
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struct super_block *s;
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struct dentry *root;
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struct btrfs_fs_devices *fs_devices = NULL;
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+ struct btrfs_root *tree_root = NULL;
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+ struct btrfs_fs_info *fs_info = NULL;
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fmode_t mode = FMODE_READ;
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char *subvol_name = NULL;
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u64 subvol_objectid = 0;
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@@ -601,8 +611,24 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags,
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goto error_close_devices;
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}
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+ /*
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+ * Setup a dummy root and fs_info for test/set super. This is because
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+ * we don't actually fill this stuff out until open_ctree, but we need
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+ * it for searching for existing supers, so this lets us do that and
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+ * then open_ctree will properly initialize everything later.
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+ */
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+ fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS);
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+ tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
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+ if (!fs_info || !tree_root) {
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+ error = -ENOMEM;
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+ goto error_close_devices;
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+ }
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+ fs_info->tree_root = tree_root;
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+ fs_info->fs_devices = fs_devices;
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+ tree_root->fs_info = fs_info;
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+
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bdev = fs_devices->latest_bdev;
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- s = sget(fs_type, btrfs_test_super, set_anon_super, fs_devices);
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+ s = sget(fs_type, btrfs_test_super, btrfs_set_super, tree_root);
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if (IS_ERR(s))
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goto error_s;
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@@ -672,6 +698,8 @@ error_s:
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error = PTR_ERR(s);
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error_close_devices:
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btrfs_close_devices(fs_devices);
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+ kfree(fs_info);
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+ kfree(tree_root);
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error_free_subvol_name:
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kfree(subvol_name);
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return error;
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--
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1.7.3.3
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