| Message ID | 1425025599-30048-5-git-send-email-quwenruo@cn.fujitsu.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
-------- Original Message -------- Subject: Re: [PATCH 4/7] btrfs-progs: Allow parse_qgroupid() to resolve subvolume path into qgroupid. From: Wang Shilong <wangshilong1991@gmail.com> To: Qu Wenruo <quwenruo@cn.fujitsu.com> Date: 2015?02?27? 16:41 > >> >> Now parse_qgroupid() can resolve subvolume path into qgroupid. >> This is quite handy for handling level 0 qgroupid, and user don't need >> to resolve rootid by hand now. > > oh, not sure if this is safe, for example, if user do something like: > > # btrfs sub create 258(subvolume id = 300) > > if 258 is passing, so it will be treated as subvolume id? Immediate number has higher privilege than path, so 258 is first considered as a subvolid and path will not be resolved, just as the old days. If user really want to do things like that, passing "./258" will be the best method. Thanks, Qu > > >> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> >> --- >> utils.c | 46 ++++++++++++++++++++++++++++++++++++++++++---- >> 1 file changed, 42 insertions(+), 4 deletions(-) >> >> diff --git a/utils.c b/utils.c >> index fc2791b..509c5ec 100644 >> --- a/utils.c >> +++ b/utils.c >> @@ -1708,6 +1708,25 @@ scan_again: >> } >> >> /* >> + * Unsafe subvolume check. >> + * >> + * This only checks ino == BTRFS_FIRST_FREE_OBJECTID, even it is not in a >> + * btrfs mount point. >> + * Must use together with other reliable method like btrfs ioctl. >> + */ >> +static int __is_subvol(char *path) >> +{ >> + struct stat st; >> + int ret; >> + >> + ret = lstat(path, &st); >> + if (ret < 0) >> + return ret; >> + >> + return st.st_ino == BTRFS_FIRST_FREE_OBJECTID; >> +} >> + >> +/* >> * A not-so-good version fls64. No fascinating optimization since >> * no one except parse_size use it >> */ >> @@ -1802,24 +1821,43 @@ u64 parse_qgroupid(char *p) >> char *ptr_parse_end = NULL; >> u64 level; >> u64 id; >> + int fd; >> + int ret = 0; >> >> + if (p[0] == '/') >> + goto path; >> + >> + /* Numeric format like '0/257' is the primary case */ >> if (!s) { >> id = strtoull(p, &ptr_parse_end, 10); >> if (ptr_parse_end != ptr_src_end) >> - goto err; >> + goto path; >> return id; >> } >> level = strtoull(p, &ptr_parse_end, 10); >> if (ptr_parse_end != s) >> - goto err; >> + goto path; >> >> id = strtoull(s+1, &ptr_parse_end, 10); >> if (ptr_parse_end != ptr_src_end) >> - goto err; >> + goto path; >> >> return (level << BTRFS_QGROUP_LEVEL_SHIFT) | id; >> +path: >> + /* Path format like subv at 'my_subvol' is the fallback case */ >> + ret = __is_subvol(p); >> + if (ret < 0 || !ret) >> + goto err; >> + fd = open(p, O_RDONLY); >> + if (fd < 0) >> + goto err; >> + ret = lookup_ino_rootid(fd, &id); >> + close(fd); >> + if (ret < 0) >> + goto err; >> + return id; >> err: >> - fprintf(stderr, "ERROR:invalid qgroupid\n"); >> + fprintf(stderr, "ERROR:invalid qgroupid or subvolume path\n"); >> exit(-1); >> } >> >> -- >> 2.3.0 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > Best Regards, > Wang Shilong > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/utils.c b/utils.c index fc2791b..509c5ec 100644 --- a/utils.c +++ b/utils.c @@ -1708,6 +1708,25 @@ scan_again: } /* + * Unsafe subvolume check. + * + * This only checks ino == BTRFS_FIRST_FREE_OBJECTID, even it is not in a + * btrfs mount point. + * Must use together with other reliable method like btrfs ioctl. + */ +static int __is_subvol(char *path) +{ + struct stat st; + int ret; + + ret = lstat(path, &st); + if (ret < 0) + return ret; + + return st.st_ino == BTRFS_FIRST_FREE_OBJECTID; +} + +/* * A not-so-good version fls64. No fascinating optimization since * no one except parse_size use it */ @@ -1802,24 +1821,43 @@ u64 parse_qgroupid(char *p) char *ptr_parse_end = NULL; u64 level; u64 id; + int fd; + int ret = 0; + if (p[0] == '/') + goto path; + + /* Numeric format like '0/257' is the primary case */ if (!s) { id = strtoull(p, &ptr_parse_end, 10); if (ptr_parse_end != ptr_src_end) - goto err; + goto path; return id; } level = strtoull(p, &ptr_parse_end, 10); if (ptr_parse_end != s) - goto err; + goto path; id = strtoull(s+1, &ptr_parse_end, 10); if (ptr_parse_end != ptr_src_end) - goto err; + goto path; return (level << BTRFS_QGROUP_LEVEL_SHIFT) | id; +path: + /* Path format like subv at 'my_subvol' is the fallback case */ + ret = __is_subvol(p); + if (ret < 0 || !ret) + goto err; + fd = open(p, O_RDONLY); + if (fd < 0) + goto err; + ret = lookup_ino_rootid(fd, &id); + close(fd); + if (ret < 0) + goto err; + return id; err: - fprintf(stderr, "ERROR:invalid qgroupid\n"); + fprintf(stderr, "ERROR:invalid qgroupid or subvolume path\n"); exit(-1); }
Now parse_qgroupid() can resolve subvolume path into qgroupid. This is quite handy for handling level 0 qgroupid, and user don't need to resolve rootid by hand now. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> --- utils.c | 46 ++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 42 insertions(+), 4 deletions(-)