btrfs: sanity mount option parsing and early mount code
Also adds lots of comments to describe what's going on here. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Christoph Hellwig
Chris Mason
Родитель
306929f364
Коммит
edf24abe51
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@ -1616,7 +1616,6 @@ int btrfs_delete_xattrs(struct btrfs_trans_handle *trans,
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struct btrfs_root *root, struct inode *inode);
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/* super.c */
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u64 btrfs_parse_size(char *str);
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int btrfs_parse_options(char *options, struct btrfs_root *root,
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char **subvol_name);
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int btrfs_parse_options(struct btrfs_root *root, char *options);
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int btrfs_sync_fs(struct super_block *sb, int wait);
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#endif
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@ -1266,8 +1266,11 @@ struct btrfs_root *open_ctree(struct super_block *sb,
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if (!btrfs_super_root(disk_super))
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goto fail_sb_buffer;
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btrfs_parse_options(options, tree_root, NULL);
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err = btrfs_parse_options(tree_root, options);
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if (err)
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goto fail_sb_buffer;
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err = -EINVAL;
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if (btrfs_super_num_devices(disk_super) > fs_devices->open_devices) {
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printk("Btrfs: wanted %llu devices, but found %llu\n",
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(unsigned long long)btrfs_super_num_devices(disk_super),
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237
fs/btrfs/super.c
237
fs/btrfs/super.c
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@ -108,15 +108,18 @@ u64 btrfs_parse_size(char *str)
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return res;
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}
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int btrfs_parse_options(char *options, struct btrfs_root *root,
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char **subvol_name)
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/*
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* Regular mount options parser. Everything that is needed only when
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* reading in a new superblock is parsed here.
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*/
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int btrfs_parse_options(struct btrfs_root *root, char *options)
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{
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char * p;
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struct btrfs_fs_info *info = NULL;
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struct btrfs_fs_info *info = root->fs_info;
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substring_t args[MAX_OPT_ARGS];
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char *p, *num;
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if (!options)
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return 1;
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return 0;
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/*
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* strsep changes the string, duplicate it because parse_options
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@ -126,10 +129,8 @@ int btrfs_parse_options(char *options, struct btrfs_root *root,
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if (!options)
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return -ENOMEM;
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if (root)
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info = root->fs_info;
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while ((p = strsep (&options, ",")) != NULL) {
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while ((p = strsep(&options, ",")) != NULL) {
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int token;
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if (!*p)
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continue;
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@ -137,83 +138,64 @@ int btrfs_parse_options(char *options, struct btrfs_root *root,
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token = match_token(p, tokens, args);
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switch (token) {
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case Opt_degraded:
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if (info) {
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printk("btrfs: allowing degraded mounts\n");
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btrfs_set_opt(info->mount_opt, DEGRADED);
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}
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printk(KERN_INFO "btrfs: allowing degraded mounts\n");
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btrfs_set_opt(info->mount_opt, DEGRADED);
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break;
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case Opt_subvol:
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if (subvol_name) {
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*subvol_name = match_strdup(&args[0]);
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}
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/*
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* This one is parsed by btrfs_parse_early_options
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* and can be happily ignored here.
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*/
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break;
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case Opt_nodatasum:
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if (info) {
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printk("btrfs: setting nodatacsum\n");
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btrfs_set_opt(info->mount_opt, NODATASUM);
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}
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printk(KERN_INFO "btrfs: setting nodatacsum\n");
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btrfs_set_opt(info->mount_opt, NODATASUM);
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break;
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case Opt_nodatacow:
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if (info) {
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printk("btrfs: setting nodatacow\n");
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btrfs_set_opt(info->mount_opt, NODATACOW);
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btrfs_set_opt(info->mount_opt, NODATASUM);
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}
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printk(KERN_INFO "btrfs: setting nodatacow\n");
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btrfs_set_opt(info->mount_opt, NODATACOW);
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btrfs_set_opt(info->mount_opt, NODATASUM);
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break;
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case Opt_ssd:
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if (info) {
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printk("btrfs: use ssd allocation scheme\n");
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btrfs_set_opt(info->mount_opt, SSD);
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}
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printk(KERN_INFO "btrfs: use ssd allocation scheme\n");
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btrfs_set_opt(info->mount_opt, SSD);
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break;
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case Opt_nobarrier:
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if (info) {
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printk("btrfs: turning off barriers\n");
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btrfs_set_opt(info->mount_opt, NOBARRIER);
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}
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printk(KERN_INFO "btrfs: turning off barriers\n");
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btrfs_set_opt(info->mount_opt, NOBARRIER);
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break;
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case Opt_max_extent:
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if (info) {
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char *num = match_strdup(&args[0]);
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if (num) {
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info->max_extent =
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btrfs_parse_size(num);
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kfree(num);
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num = match_strdup(&args[0]);
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if (num) {
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info->max_extent = btrfs_parse_size(num);
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kfree(num);
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info->max_extent = max_t(u64,
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info->max_extent,
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root->sectorsize);
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printk("btrfs: max_extent at %Lu\n",
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info->max_extent);
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}
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info->max_extent = max_t(u64,
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info->max_extent, root->sectorsize);
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printk(KERN_INFO "btrfs: max_extent at %llu\n",
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info->max_extent);
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}
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break;
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case Opt_max_inline:
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if (info) {
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char *num = match_strdup(&args[0]);
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if (num) {
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info->max_inline =
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btrfs_parse_size(num);
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kfree(num);
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num = match_strdup(&args[0]);
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if (num) {
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info->max_inline = btrfs_parse_size(num);
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kfree(num);
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info->max_inline = max_t(u64,
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info->max_inline,
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root->sectorsize);
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printk("btrfs: max_inline at %Lu\n",
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info->max_inline);
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}
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info->max_inline = max_t(u64,
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info->max_inline, root->sectorsize);
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printk(KERN_INFO "btrfs: max_inline at %llu\n",
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info->max_inline);
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}
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break;
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case Opt_alloc_start:
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if (info) {
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char *num = match_strdup(&args[0]);
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if (num) {
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info->alloc_start =
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btrfs_parse_size(num);
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kfree(num);
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printk("btrfs: allocations start at "
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"%Lu\n", info->alloc_start);
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}
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num = match_strdup(&args[0]);
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if (num) {
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info->alloc_start = btrfs_parse_size(num);
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kfree(num);
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printk(KERN_INFO
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"btrfs: allocations start at %llu\n",
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info->alloc_start);
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}
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break;
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default:
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@ -221,7 +203,61 @@ int btrfs_parse_options(char *options, struct btrfs_root *root,
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}
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}
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kfree(options);
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return 1;
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return 0;
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}
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/*
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* Parse mount options that are required early in the mount process.
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*
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* All other options will be parsed on much later in the mount process and
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* only when we need to allocate a new super block.
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*/
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static int btrfs_parse_early_options(const char *options,
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char **subvol_name)
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{
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substring_t args[MAX_OPT_ARGS];
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char *opts, *p;
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int error = 0;
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if (!options)
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goto out;
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/*
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* strsep changes the string, duplicate it because parse_options
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* gets called twice
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*/
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opts = kstrdup(options, GFP_KERNEL);
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if (!opts)
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return -ENOMEM;
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while ((p = strsep(&opts, ",")) != NULL) {
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int token;
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if (!*p)
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continue;
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token = match_token(p, tokens, args);
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switch (token) {
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case Opt_subvol:
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*subvol_name = match_strdup(&args[0]);
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break;
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default:
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break;
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}
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}
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kfree(opts);
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out:
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/*
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* If no subvolume name is specified we use the default one. Allocate
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* a copy of the string "default" here so that code later in the
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* mount path doesn't care if it's the default volume or another one.
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*/
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if (!*subvol_name) {
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*subvol_name = kstrdup("default", GFP_KERNEL);
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if (!*subvol_name)
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return -ENOMEM;
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}
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return error;
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}
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static int btrfs_fill_super(struct super_block * sb,
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@ -328,23 +364,33 @@ static int btrfs_test_super(struct super_block *s, void *data)
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return root->fs_info->fs_devices == test_fs_devices;
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}
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int btrfs_get_sb_bdev(struct file_system_type *fs_type,
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int flags, const char *dev_name, void *data,
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struct vfsmount *mnt, const char *subvol)
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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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* Note: This is based on get_sb_bdev from fs/super.c with a few additions
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* for multiple device setup. Make sure to keep it in sync.
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*/
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static int btrfs_get_sb(struct file_system_type *fs_type, int flags,
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const char *dev_name, void *data, struct vfsmount *mnt)
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{
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char *subvol_name = NULL;
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struct block_device *bdev = NULL;
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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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int error = 0;
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error = btrfs_parse_early_options(data, &subvol_name);
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if (error)
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goto error;
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error = btrfs_scan_one_device(dev_name, flags, fs_type, &fs_devices);
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if (error)
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return error;
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goto error_free_subvol_name;
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error = btrfs_open_devices(fs_devices, flags, fs_type);
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if (error)
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return error;
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goto error_free_subvol_name;
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bdev = fs_devices->latest_bdev;
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btrfs_lock_volumes();
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@ -378,51 +424,36 @@ int btrfs_get_sb_bdev(struct file_system_type *fs_type,
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s->s_flags |= MS_ACTIVE;
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}
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if (subvol) {
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root = lookup_one_len(subvol, s->s_root, strlen(subvol));
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if (IS_ERR(root)) {
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up_write(&s->s_umount);
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deactivate_super(s);
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error = PTR_ERR(root);
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goto error;
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}
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if (!root->d_inode) {
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dput(root);
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up_write(&s->s_umount);
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deactivate_super(s);
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error = -ENXIO;
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goto error;
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}
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} else {
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root = dget(s->s_root);
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root = lookup_one_len(subvol_name, s->s_root, strlen(subvol_name));
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if (IS_ERR(root)) {
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up_write(&s->s_umount);
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deactivate_super(s);
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error = PTR_ERR(root);
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goto error;
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}
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if (!root->d_inode) {
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dput(root);
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up_write(&s->s_umount);
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deactivate_super(s);
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error = -ENXIO;
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goto error;
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}
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mnt->mnt_sb = s;
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mnt->mnt_root = root;
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kfree(subvol_name);
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return 0;
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error_s:
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error = PTR_ERR(s);
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error_bdev:
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btrfs_close_devices(fs_devices);
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error_free_subvol_name:
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kfree(subvol_name);
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error:
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return error;
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}
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/* end copy & paste */
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static int btrfs_get_sb(struct file_system_type *fs_type,
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int flags, const char *dev_name, void *data, struct vfsmount *mnt)
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{
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int ret;
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char *subvol_name = NULL;
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btrfs_parse_options((char *)data, NULL, &subvol_name);
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ret = btrfs_get_sb_bdev(fs_type, flags, dev_name, data, mnt,
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subvol_name ? subvol_name : "default");
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if (subvol_name)
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kfree(subvol_name);
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return ret;
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}
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static int btrfs_statfs(struct dentry *dentry, struct kstatfs *buf)
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{
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