From 0de90876c6cb774d4a424dafc1fc9ec50071b81b Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Fri, 19 Nov 2010 13:40:41 +0000 Subject: Btrfs: handle the space_cache option properly When I added the clear_cache option I screwed up and took the break out of the space_cache case statement, so whenever you mount with space_cache you also get clear_cache, which does you no good if you say set space_cache in fstab so it always gets set. This patch adds the break back in properly. Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/super.c | 1 + 1 file changed, 1 insertion(+) (limited to 'fs/btrfs/super.c') diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 718b10de2049..66e4612a7916 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -244,6 +244,7 @@ int btrfs_parse_options(struct btrfs_root *root, char *options) case Opt_space_cache: printk(KERN_INFO "btrfs: enabling disk space caching\n"); btrfs_set_opt(info->mount_opt, SPACE_CACHE); + break; case Opt_clear_cache: printk(KERN_INFO "btrfs: force clearing of disk cache\n"); btrfs_set_opt(info->mount_opt, CLEAR_CACHE); -- cgit v1.2.3 From 619c8c763928841b1112e1d417f88bc1d44daecb Mon Sep 17 00:00:00 2001 From: Ian Kent Date: Mon, 22 Nov 2010 02:21:38 +0000 Subject: Btrfs - fix race between btrfs_get_sb() and umount When mounting a btrfs file system btrfs_test_super() may attempt to use sb->s_fs_info, the btrfs root, of a super block that is going away and that has had the btrfs root set to NULL in its ->put_super(). But if the super block is going away it cannot be an existing super block so we can return false in this case. Signed-off-by: Ian Kent Signed-off-by: Chris Mason --- fs/btrfs/super.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'fs/btrfs/super.c') diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 66e4612a7916..141fb317d3bc 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -566,6 +566,12 @@ static int btrfs_test_super(struct super_block *s, void *data) struct btrfs_fs_devices *test_fs_devices = data; struct btrfs_root *root = btrfs_sb(s); + /* + * If this super block is going away, return false as it + * can't match as an existing super block. + */ + if (!atomic_read(&s->s_active)) + return 0; return root->fs_info->fs_devices == test_fs_devices; } -- cgit v1.2.3 From 450ba0ea06b6ed3612d27f2b7127a9de4160f285 Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Fri, 19 Nov 2010 14:59:15 -0500 Subject: 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 Signed-off-by: Chris Mason --- fs/btrfs/disk-io.c | 6 ++---- fs/btrfs/super.c | 34 +++++++++++++++++++++++++++++++--- 2 files changed, 33 insertions(+), 7 deletions(-) (limited to 'fs/btrfs/super.c') diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index a67b98d58c2a..57c9d8eeb7dc 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 141fb317d3bc..47bf67cbe6bf 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; -- cgit v1.2.3 From f106e82caaa0d943e47cacc184f5b40d538e0044 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Tue, 7 Dec 2010 01:51:26 +0000 Subject: Btrfs: Fix a crash when mounting a subvolume We should drop dentry before deactivating the superblock, otherwise we can hit this bug: BUG: Dentry f349a690{i=100,n=/} still in use (1) [unmount of btrfs loop1] ... Steps to reproduce the bug: # mount /dev/loop1 /mnt # mkdir save # btrfs subvolume snapshot /mnt save/snap1 # umount /mnt # mount -o subvol=save/snap1 /dev/loop1 /mnt (crash) Reported-by: Michael Niederle Signed-off-by: Li Zefan Signed-off-by: Chris Mason --- fs/btrfs/super.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/btrfs/super.c') diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 47bf67cbe6bf..61bd79abb805 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -685,9 +685,9 @@ static int btrfs_get_sb(struct file_system_type *fs_type, int flags, mutex_unlock(&root->d_inode->i_mutex); if (IS_ERR(new_root)) { + dput(root); deactivate_locked_super(s); error = PTR_ERR(new_root); - dput(root); goto error_free_subvol_name; } if (!new_root->d_inode) { -- cgit v1.2.3