Some programs like btrfsck should not be run on a mounted filesystem. This patch adds a check in btrfs_open_devices() for the mount status of every device belonging to the filesystem. The function check_mount() gets improved support for loopback devices. It now detects if the program is run on the file that is being used by the loopback device.
Signed-off-by: Andi Drebes <[email protected]> --- diff --git a/btrfs-map-logical.c b/btrfs-map-logical.c index a109c6a..1e0ef9f 100644 --- a/btrfs-map-logical.c +++ b/btrfs-map-logical.c @@ -169,7 +169,7 @@ int main(int ac, char **av) radix_tree_init(); cache_tree_init(&root_cache); - root = open_ctree(dev, 0, 0); + root = open_ctree(dev, 0, 0, 0); if (!root) { fprintf(stderr, "Open ctree failed\n"); exit(1); diff --git a/btrfsck.c b/btrfsck.c index 73f1836..1434791 100644 --- a/btrfsck.c +++ b/btrfsck.c @@ -2821,7 +2821,7 @@ int main(int ac, char **av) radix_tree_init(); cache_tree_init(&root_cache); - root = open_ctree(av[1], 0, 0); + root = open_ctree(av[1], 0, 0, 1); if (root == NULL) return 1; diff --git a/debug-tree.c b/debug-tree.c index 1d47519..a8e85f4 100644 --- a/debug-tree.c +++ b/debug-tree.c @@ -137,7 +137,7 @@ int main(int ac, char **av) if (ac != 1) print_usage(); - root = open_ctree(av[optind], 0, 0); + root = open_ctree(av[optind], 0, 0, 0); if (!root) { fprintf(stderr, "unable to open %s\n", av[optind]); exit(1); diff --git a/disk-io.c b/disk-io.c index addebe1..f8e623b 100644 --- a/disk-io.c +++ b/disk-io.c @@ -570,7 +570,7 @@ struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info, return root; } -struct btrfs_root *open_ctree(const char *filename, u64 sb_bytenr, int writes) +struct btrfs_root *open_ctree(const char *filename, u64 sb_bytenr, int writes, int check_mount) { int fp; struct btrfs_root *root; @@ -584,14 +584,14 @@ struct btrfs_root *open_ctree(const char *filename, u64 sb_bytenr, int writes) fprintf (stderr, "Could not open %s\n", filename); return NULL; } - root = open_ctree_fd(fp, filename, sb_bytenr, writes); + root = open_ctree_fd(fp, filename, sb_bytenr, writes, check_mount); close(fp); return root; } struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr, - int writes) + int writes, int check_mount) { u32 sectorsize; u32 nodesize; @@ -657,9 +657,9 @@ struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr, fs_info, BTRFS_ROOT_TREE_OBJECTID); if (writes) - ret = btrfs_open_devices(fs_devices, O_RDWR); + ret = btrfs_open_devices(fs_devices, O_RDWR, check_mount); else - ret = btrfs_open_devices(fs_devices, O_RDONLY); + ret = btrfs_open_devices(fs_devices, O_RDONLY, check_mount); BUG_ON(ret); fs_info->super_bytenr = sb_bytenr; @@ -725,7 +725,7 @@ struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr, BTRFS_UUID_SIZE); if (!(btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_METADUMP)) { - ret = btrfs_read_chunk_tree(chunk_root); + ret = btrfs_read_chunk_tree(chunk_root, check_mount); BUG_ON(ret); } diff --git a/disk-io.h b/disk-io.h index 49e5692..1d6519e 100644 --- a/disk-io.h +++ b/disk-io.h @@ -43,9 +43,9 @@ struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize); int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct extent_buffer *buf); -struct btrfs_root *open_ctree(const char *filename, u64 sb_bytenr, int writes); +struct btrfs_root *open_ctree(const char *filename, u64 sb_bytenr, int writes, int check_mount); struct btrfs_root *open_ctree_fd(int fp, const char *path, u64 sb_bytenr, - int writes); + int writes, int check_mount); int close_ctree(struct btrfs_root *root); int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root *root); diff --git a/kerncompat.h b/kerncompat.h index e4c8ce0..46236cd 100644 --- a/kerncompat.h +++ b/kerncompat.h @@ -42,7 +42,11 @@ #define GFP_NOFS 0 #define __read_mostly #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) + +#ifndef ULONG_MAX #define ULONG_MAX (~0UL) +#endif + #define BUG() abort() #ifdef __CHECKER__ #define __force __attribute__((force)) diff --git a/mkfs.c b/mkfs.c index 2e99b95..f226661 100644 --- a/mkfs.c +++ b/mkfs.c @@ -456,7 +456,7 @@ int main(int ac, char **av) fprintf(stderr, "error during mkfs %d\n", ret); exit(1); } - root = open_ctree(file, 0, O_RDWR); + root = open_ctree(file, 0, O_RDWR, 1); root->fs_info->alloc_start = alloc_start; ret = make_root_dir(root); diff --git a/utils.c b/utils.c index 2f4c6e1..60c3f24 100644 --- a/utils.c +++ b/utils.c @@ -31,6 +31,8 @@ #include <fcntl.h> #include <unistd.h> #include <mntent.h> +#include <linux/loop.h> +#include <limits.h> #include "kerncompat.h" #include "radix-tree.h" #include "ctree.h" @@ -586,46 +588,105 @@ error: return ret; } +int is_loop_device (const char *device) { + struct stat statbuf; + + if(stat(device, &statbuf) < 0) + return -errno; + + return (S_ISBLK(statbuf.st_mode) && + major(statbuf.st_rdev) == LOOP_MAJOR); +} + +int is_same_blk_file(const char* a, const char* b) +{ + struct stat st_buf_a, st_buf_b; + char real_a[PATH_MAX]; + char real_b[PATH_MAX]; + + if(!realpath(a, real_a) || + !realpath(b, real_b)) + { + return -errno; + } + + /* Identical path? */ + if(strcmp(real_a, real_b) == 0) + return 1; + + if(stat(a, &st_buf_a) < 0 || + stat(b, &st_buf_b) < 0) + { + return -errno; + } + + /* Same blockdevice? */ + if(S_ISBLK(st_buf_a.st_mode) && + S_ISBLK(st_buf_b.st_mode) && + st_buf_a.st_rdev == st_buf_b.st_rdev) + { + return 1; + } + + /* Hardlink? */ + if (st_buf_a.st_dev == st_buf_b.st_dev && + st_buf_a.st_ino == st_buf_b.st_ino) + { + return 1; + } + + return 0; +} + /* * returns 1 if the device was mounted, < 0 on error or 0 if everything - * is safe to continue. TODO, this should also scan multi-device filesystems + * is safe to continue. */ int check_mounted(char *file) { struct mntent *mnt; - struct stat st_buf; - dev_t file_dev = 0; - dev_t file_rdev = 0; - ino_t file_ino = 0; FILE *f; int ret = 0; - if ((f = setmntent ("/proc/mounts", "r")) == NULL) - return -errno; + int loop_fd; + struct loop_info loopinfo; - if (stat(file, &st_buf) < 0) { + if ((f = setmntent ("/proc/mounts", "r")) == NULL) return -errno; - } else { - if (S_ISBLK(st_buf.st_mode)) { - file_rdev = st_buf.st_rdev; - } else { - file_dev = st_buf.st_dev; - file_ino = st_buf.st_ino; - } - } while ((mnt = getmntent (f)) != NULL) { - if (strcmp(file, mnt->mnt_fsname) == 0) - break; + /* Only check btrfs filesystems */ + if(strcmp(mnt->mnt_type, "btrfs") != 0) + continue; - if (stat(mnt->mnt_fsname, &st_buf) == 0) { - if (S_ISBLK(st_buf.st_mode)) { - if (file_rdev && (file_rdev == st_buf.st_rdev)) - break; - } else if (file_dev && ((file_dev == st_buf.st_dev) && - (file_ino == st_buf.st_ino))) { + ret = is_loop_device(mnt->mnt_fsname); + + if(ret < 0) + goto out_err; + + if(ret) { + /* Current entry is a loop device */ + if ((loop_fd = open(mnt->mnt_fsname, O_RDONLY)) < 0) { + ret = -errno; + goto out_err; + } + + /* Get loop device info and check */ + if (ioctl(loop_fd, LOOP_GET_STATUS, &loopinfo) == 0) { + ret = is_same_blk_file(file, loopinfo.lo_name); + + if(ret < 0) + goto out_err; + else if(ret) break; + } else { + ret = -errno; + goto out_err; } + } else { + /* normal block device */ + if(is_same_blk_file(file, mnt->mnt_fsname) > 0) + break; } } @@ -634,6 +695,7 @@ int check_mounted(char *file) ret = 1; } +out_err: endmntent (f); return ret; } diff --git a/utils.h b/utils.h index 7ff542b..695686b 100644 --- a/utils.h +++ b/utils.h @@ -19,6 +19,12 @@ #ifndef __UTILS__ #define __UTILS__ +#define LOOP_MAJOR 7 + +#ifndef major +#define major(dev) ((dev) >> 8) +#endif + #define BTRFS_MKFS_SYSTEM_GROUP_SIZE (4 * 1024 * 1024) int make_btrfs(int fd, const char *device, const char *label, diff --git a/volumes.c b/volumes.c index 7671855..467f552 100644 --- a/volumes.c +++ b/volumes.c @@ -29,6 +29,7 @@ #include "transaction.h" #include "print-tree.h" #include "volumes.h" +#include "utils.h" struct stripe { struct btrfs_device *dev; @@ -164,7 +165,7 @@ again: return 0; } -int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, int flags) +int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, int flags, int check_mount) { int fd; struct list_head *head = &fs_devices->devices; @@ -175,6 +176,19 @@ int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, int flags) list_for_each(cur, head) { device = list_entry(cur, struct btrfs_device, dev_list); + if(check_mount) { + ret = check_mounted(device->name); + if (ret < 0) { + fprintf(stderr, "error checking %s mount status\n", device->name); + goto fail; + } + if (ret == 1) { + fprintf(stderr, "Error: %s is currently mounted.\n", device->name); + ret = -EBUSY; + goto fail; + } + } + fd = open(device->name, flags); if (fd < 0) { ret = -errno; @@ -1240,7 +1254,7 @@ static int fill_device_from_item(struct extent_buffer *leaf, return 0; } -static int open_seed_devices(struct btrfs_root *root, u8 *fsid) +static int open_seed_devices(struct btrfs_root *root, u8 *fsid, int check_mount) { struct btrfs_fs_devices *fs_devices; int ret; @@ -1260,7 +1274,7 @@ static int open_seed_devices(struct btrfs_root *root, u8 *fsid) goto out; } - ret = btrfs_open_devices(fs_devices, O_RDONLY); + ret = btrfs_open_devices(fs_devices, O_RDONLY, check_mount); if (ret) goto out; @@ -1272,7 +1286,8 @@ out: static int read_one_dev(struct btrfs_root *root, struct extent_buffer *leaf, - struct btrfs_dev_item *dev_item) + struct btrfs_dev_item *dev_item, + int check_mount) { struct btrfs_device *device; u64 devid; @@ -1289,7 +1304,7 @@ static int read_one_dev(struct btrfs_root *root, BTRFS_UUID_SIZE); if (memcmp(fs_uuid, root->fs_info->fsid, BTRFS_UUID_SIZE)) { - ret = open_seed_devices(root, fs_uuid); + ret = open_seed_devices(root, fs_uuid, check_mount); if (ret) return ret; } @@ -1311,13 +1326,13 @@ static int read_one_dev(struct btrfs_root *root, return ret; } -int btrfs_read_super_device(struct btrfs_root *root, struct extent_buffer *buf) +int btrfs_read_super_device(struct btrfs_root *root, struct extent_buffer *buf, int check_mount) { struct btrfs_dev_item *dev_item; dev_item = (struct btrfs_dev_item *)offsetof(struct btrfs_super_block, dev_item); - return read_one_dev(root, buf, dev_item); + return read_one_dev(root, buf, dev_item, check_mount); } int btrfs_read_sys_array(struct btrfs_root *root) @@ -1378,7 +1393,7 @@ int btrfs_read_sys_array(struct btrfs_root *root) return 0; } -int btrfs_read_chunk_tree(struct btrfs_root *root) +int btrfs_read_chunk_tree(struct btrfs_root *root, int check_mount) { struct btrfs_path *path; struct extent_buffer *leaf; @@ -1421,7 +1436,7 @@ again: struct btrfs_dev_item *dev_item; dev_item = btrfs_item_ptr(leaf, slot, struct btrfs_dev_item); - ret = read_one_dev(root, leaf, dev_item); + ret = read_one_dev(root, leaf, dev_item, check_mount); BUG_ON(ret); } } else if (found_key.type == BTRFS_CHUNK_ITEM_KEY) { diff --git a/volumes.h b/volumes.h index bb78751..baf12ff 100644 --- a/volumes.h +++ b/volumes.h @@ -103,16 +103,16 @@ int btrfs_rmap_block(struct btrfs_mapping_tree *map_tree, u64 chunk_start, u64 physical, u64 devid, u64 **logical, int *naddrs, int *stripe_len); int btrfs_read_sys_array(struct btrfs_root *root); -int btrfs_read_chunk_tree(struct btrfs_root *root); +int btrfs_read_chunk_tree(struct btrfs_root *root, int check_mount); int btrfs_alloc_chunk(struct btrfs_trans_handle *trans, struct btrfs_root *extent_root, u64 *start, u64 *num_bytes, u64 type); -int btrfs_read_super_device(struct btrfs_root *root, struct extent_buffer *buf); +int btrfs_read_super_device(struct btrfs_root *root, struct extent_buffer *buf, int check_mount); int btrfs_add_device(struct btrfs_trans_handle *trans, struct btrfs_root *root, struct btrfs_device *device); int btrfs_open_devices(struct btrfs_fs_devices *fs_devices, - int flags); + int flags, int check_mount); int btrfs_close_devices(struct btrfs_fs_devices *fs_devices); int btrfs_add_device(struct btrfs_trans_handle *trans, struct btrfs_root *root, -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
