From 04d21a244fdf79d0ac892eaaa9a46b682467277c Mon Sep 17 00:00:00 2001 From: Ilya Dryomov Date: Wed, 9 Nov 2011 14:41:22 +0200 Subject: Btrfs: rework error handling in btrfs_mount() Commits 6c41761f and 45ea6095 introduced the possibility of NULL pointer dereference on error paths, also we would leave all devices busy and leak fs_info with all sub-structures on error when trying to mount an already mounted fs to a different directory. Fix this by doing all allocations before trying to open any of the devices, adjust error path for mount-already-mounted-fs case. Signed-off-by: Ilya Dryomov --- fs/btrfs/super.c | 42 +++++++++++++++++++++--------------------- 1 file changed, 21 insertions(+), 21 deletions(-) (limited to 'fs') diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 58e9492230ce..629281c65ff5 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -891,7 +891,6 @@ static struct dentry *btrfs_mount(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; @@ -920,15 +919,6 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags, if (error) return ERR_PTR(error); - error = btrfs_open_devices(fs_devices, mode, fs_type); - if (error) - return ERR_PTR(error); - - if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) { - error = -EACCES; - 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 @@ -936,28 +926,36 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags, * then open_ctree will properly initialize everything later. */ fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS); - if (!fs_info) { - error = -ENOMEM; - goto error_close_devices; - } - tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS); - if (!tree_root) { + if (!fs_info) + return ERR_PTR(-ENOMEM); + + fs_info->tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS); + if (!fs_info->tree_root) { error = -ENOMEM; - goto error_close_devices; + goto error_fs_info; } - fs_info->tree_root = tree_root; + fs_info->tree_root->fs_info = fs_info; fs_info->fs_devices = fs_devices; - tree_root->fs_info = fs_info; fs_info->super_copy = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS); fs_info->super_for_commit = kzalloc(BTRFS_SUPER_INFO_SIZE, GFP_NOFS); if (!fs_info->super_copy || !fs_info->super_for_commit) { error = -ENOMEM; + goto error_fs_info; + } + + error = btrfs_open_devices(fs_devices, mode, fs_type); + if (error) + goto error_fs_info; + + if (!(flags & MS_RDONLY) && fs_devices->rw_devices == 0) { + error = -EACCES; goto error_close_devices; } bdev = fs_devices->latest_bdev; - s = sget(fs_type, btrfs_test_super, btrfs_set_super, tree_root); + s = sget(fs_type, btrfs_test_super, btrfs_set_super, + fs_info->tree_root); if (IS_ERR(s)) { error = PTR_ERR(s); goto error_close_devices; @@ -966,7 +964,8 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags, if (s->s_root) { if ((flags ^ s->s_flags) & MS_RDONLY) { deactivate_locked_super(s); - return ERR_PTR(-EBUSY); + error = -EBUSY; + goto error_close_devices; } btrfs_close_devices(fs_devices); @@ -997,6 +996,7 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags, error_close_devices: btrfs_close_devices(fs_devices); +error_fs_info: free_fs_info(fs_info); return ERR_PTR(error); } -- cgit v1.2.3