On Sun, Nov 15, 2009 at 2:44 AM, Andi Drebes
<lists-receive@xxxxxxxxxxxxxxxxxxx> wrote:
> 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.
>
Hi Andi,
Thank you for sending the patch.
Would you please add mounted check for multiple devices FS to
check_mounted instead of btrfs_open_devices. It's easy to get the
list of devices, see code at very beginning of open_ctree_fd().
Yan, Zheng
> ---besides
> 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,
> --
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