thr3ads.net - Btrfs devel - [PATCH V2] Btrfs: fix subvolume mount by name problem when default mount subvolume is set [Apr 2011]

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Zhong, Xin

2011-Apr-06 05:27 UTC

[PATCH V2] Btrfs: fix subvolume mount by name problem when default mount subvolume is set

We create two subvolumes (meego_root and meego_home) in
btrfs root directory. And set meego_root as default mount
subvolume. After we remount btrfs, meego_root is mounted
to top directory by default. Then when we try to mount
meego_home (subvol=meego_home) to a subdirectory, it failed.
The problem is when default mount subvolume is set to
meego_root, we search meego_home in meego_root but can not find
it. So the solution is to add a new mount option (subvolrootid)
to specify subvol id of root and search subvol name in it. For
our case, now we can use "-o subvolrootid=0,subvol=meego_home)
to mount meego_home.

Detail information can be found in meego bugzilla:
https://bugs.meego.com/show_bug.cgi?id=15055

Signed-off-by: Zhong, Xin <xin.zhong@intel.com>
---
 fs/btrfs/super.c |   43 ++++++++++++++++++++++++++++++++++---------
 1 files changed, 34 insertions(+), 9 deletions(-)

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index db0a827..cd5f3ad 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -156,7 +156,7 @@ enum {
 	Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
 	Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
 	Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
-	Opt_enospc_debug, Opt_err,
+	Opt_enospc_debug, Opt_subvolrootid, Opt_err,
 };
 
 static match_table_t tokens = {
@@ -186,6 +186,7 @@ static match_table_t tokens = {
 	{Opt_clear_cache, "clear_cache"},
 	{Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 	{Opt_enospc_debug, "enospc_debug"},
+	{Opt_subvolrootid, "subvolrootid=%d"},
 	{Opt_err, NULL},
 };
 
@@ -229,6 +230,7 @@ int btrfs_parse_options(struct btrfs_root *root, char
*options)
 			break;
 		case Opt_subvol:
 		case Opt_subvolid:
+		case Opt_subvolrootid:
 		case Opt_device:
 			/*
 			 * These are parsed by btrfs_parse_early_options
@@ -385,7 +387,7 @@ out:
  */
 static int btrfs_parse_early_options(const char *options, fmode_t flags,
 		void *holder, char **subvol_name, u64 *subvol_objectid,
-		struct btrfs_fs_devices **fs_devices)
+		u64 *subvol_rootid, struct btrfs_fs_devices **fs_devices)
 {
 	substring_t args[MAX_OPT_ARGS];
 	char *opts, *orig, *p;
@@ -426,6 +428,18 @@ static int btrfs_parse_early_options(const char *options,
fmode_t flags,
 					*subvol_objectid = intarg;
 			}
 			break;
+		case Opt_subvolrootid:
+			intarg = 0;
+			error = match_int(&args[0], &intarg);
+			if (!error) {
+				/* we want the original fs_tree */
+				if (!intarg)
+					*subvol_rootid +						BTRFS_FS_TREE_OBJECTID;
+				else
+					*subvol_rootid = intarg;
+			}
+			break;
 		case Opt_device:
 			error = btrfs_scan_one_device(match_strdup(&args[0]),
 					flags, holder, fs_devices);
@@ -715,6 +729,7 @@ static int btrfs_get_sb(struct file_system_type *fs_type,
int flags,
 	fmode_t mode = FMODE_READ;
 	char *subvol_name = NULL;
 	u64 subvol_objectid = 0;
+	u64 subvol_rootid = 0;
 	int error = 0;
 
 	if (!(flags & MS_RDONLY))
@@ -722,7 +737,7 @@ static int btrfs_get_sb(struct file_system_type *fs_type,
int flags,
 
 	error = btrfs_parse_early_options(data, mode, fs_type,
 					  &subvol_name, &subvol_objectid,
-					  &fs_devices);
+					  &subvol_rootid, &fs_devices);
 	if (error)
 		return error;
 
@@ -786,15 +801,17 @@ static int btrfs_get_sb(struct file_system_type *fs_type,
int flags,
 		s->s_flags |= MS_ACTIVE;
 	}
 
-	root = get_default_root(s, subvol_objectid);
-	if (IS_ERR(root)) {
-		error = PTR_ERR(root);
-		deactivate_locked_super(s);
-		goto error_free_subvol_name;
-	}
 	/* if they gave us a subvolume name bind mount into that */
 	if (strcmp(subvol_name, ".")) {
 		struct dentry *new_root;
+		
+		root = get_default_root(s, subvol_rootid);
+		if (IS_ERR(root)) {
+			error = PTR_ERR(root);
+			deactivate_locked_super(s);
+			goto error_free_subvol_name;
+		}
+
 		mutex_lock(&root->d_inode->i_mutex);
 		new_root = lookup_one_len(subvol_name, root,
 				      strlen(subvol_name));
@@ -816,6 +833,14 @@ static int btrfs_get_sb(struct file_system_type *fs_type,
int flags,
 		dput(root);
 		root = new_root;
 	}
+	else {
+		root = get_default_root(s, subvol_objectid);
+		if (IS_ERR(root)) {
+			error = PTR_ERR(root);
+			deactivate_locked_super(s);
+			goto error_free_subvol_name;
+		}
+	}
 
 	mnt->mnt_sb = s;
 	mnt->mnt_root = root;
-- 
1.7.0.4

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Li Zefan

2011-Apr-06 06:34 UTC

head link

Re: [PATCH V2] Btrfs: fix subvolume mount by name problem when default mount subvolume is set

13:27, Zhong, Xin wrote:> We create two subvolumes (meego_root and meego_home) in
> btrfs root directory. And set meego_root as default mount
> subvolume. After we remount btrfs, meego_root is mounted
> to top directory by default. Then when we try to mount
> meego_home (subvol=meego_home) to a subdirectory, it failed.
> The problem is when default mount subvolume is set to
> meego_root, we search meego_home in meego_root but can not find
> it. So the solution is to add a new mount option (subvolrootid)
> to specify subvol id of root and search subvol name in it. For
> our case, now we can use "-o subvolrootid=0,subvol=meego_home)
> to mount meego_home.
> 
> Detail information can be found in meego bugzilla:
> https://bugs.meego.com/show_bug.cgi?id=15055
> 
> Signed-off-by: Zhong, Xin <xin.zhong@intel.com>
> ---
>  fs/btrfs/super.c |   43 ++++++++++++++++++++++++++++++++++---------
>  1 files changed, 34 insertions(+), 9 deletions(-)
> 
I guess you forgot to run checkpatch.pl.

ERROR: trailing whitespace
#183: FILE: fs/btrfs/super.c:807:
+^I^I$

ERROR: else should follow close brace ''}''
#198: FILE: fs/btrfs/super.c:836:
        }
+       else {

total: 2 errors, 0 warnings, 100 lines checked
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Zhong, Xin

2011-Apr-06 07:13 UTC

head link

[PATCH V2] Btrfs: fix subvolume mount by name problem when default mount subvolume is set

We create two subvolumes (meego_root and meego_home) in
btrfs root directory. And set meego_root as default mount
subvolume. After we remount btrfs, meego_root is mounted
to top directory by default. Then when we try to mount
meego_home (subvol=meego_home) to a subdirectory, it failed.
The problem is when default mount subvolume is set to
meego_root, we search meego_home in meego_root but can not find
it. So the solution is to add a new mount option (subvolrootid)
to specify subvol id of root and search subvol name in it. For
our case, now we can use "-o subvolrootid=0,subvol=meego_home)
to mount meego_home.

Detail information can be found in meego bugzilla:
https://bugs.meego.com/show_bug.cgi?id=15055

Signed-off-by: Zhong, Xin <xin.zhong@intel.com>
---
 fs/btrfs/super.c |   43 ++++++++++++++++++++++++++++++++++---------
 1 files changed, 34 insertions(+), 9 deletions(-)

diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index db0a827..5e7bc51 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -156,7 +156,7 @@ enum {
 	Opt_compress_type, Opt_compress_force, Opt_compress_force_type,
 	Opt_notreelog, Opt_ratio, Opt_flushoncommit, Opt_discard,
 	Opt_space_cache, Opt_clear_cache, Opt_user_subvol_rm_allowed,
-	Opt_enospc_debug, Opt_err,
+	Opt_enospc_debug, Opt_subvolrootid, Opt_err,
 };
 
 static match_table_t tokens = {
@@ -186,6 +186,7 @@ static match_table_t tokens = {
 	{Opt_clear_cache, "clear_cache"},
 	{Opt_user_subvol_rm_allowed, "user_subvol_rm_allowed"},
 	{Opt_enospc_debug, "enospc_debug"},
+	{Opt_subvolrootid, "subvolrootid=%d"},
 	{Opt_err, NULL},
 };
 
@@ -229,6 +230,7 @@ int btrfs_parse_options(struct btrfs_root *root, char
*options)
 			break;
 		case Opt_subvol:
 		case Opt_subvolid:
+		case Opt_subvolrootid:
 		case Opt_device:
 			/*
 			 * These are parsed by btrfs_parse_early_options
@@ -385,7 +387,7 @@ out:
  */
 static int btrfs_parse_early_options(const char *options, fmode_t flags,
 		void *holder, char **subvol_name, u64 *subvol_objectid,
-		struct btrfs_fs_devices **fs_devices)
+		u64 *subvol_rootid, struct btrfs_fs_devices **fs_devices)
 {
 	substring_t args[MAX_OPT_ARGS];
 	char *opts, *orig, *p;
@@ -426,6 +428,18 @@ static int btrfs_parse_early_options(const char *options,
fmode_t flags,
 					*subvol_objectid = intarg;
 			}
 			break;
+		case Opt_subvolrootid:
+			intarg = 0;
+			error = match_int(&args[0], &intarg);
+			if (!error) {
+				/* we want the original fs_tree */
+				if (!intarg)
+					*subvol_rootid +						BTRFS_FS_TREE_OBJECTID;
+				else
+					*subvol_rootid = intarg;
+			}
+			break;
 		case Opt_device:
 			error = btrfs_scan_one_device(match_strdup(&args[0]),
 					flags, holder, fs_devices);
@@ -715,6 +729,7 @@ static int btrfs_get_sb(struct file_system_type *fs_type,
int flags,
 	fmode_t mode = FMODE_READ;
 	char *subvol_name = NULL;
 	u64 subvol_objectid = 0;
+	u64 subvol_rootid = 0;
 	int error = 0;
 
 	if (!(flags & MS_RDONLY))
@@ -722,7 +737,7 @@ static int btrfs_get_sb(struct file_system_type *fs_type,
int flags,
 
 	error = btrfs_parse_early_options(data, mode, fs_type,
 					  &subvol_name, &subvol_objectid,
-					  &fs_devices);
+					  &subvol_rootid, &fs_devices);
 	if (error)
 		return error;
 
@@ -786,15 +801,17 @@ static int btrfs_get_sb(struct file_system_type *fs_type,
int flags,
 		s->s_flags |= MS_ACTIVE;
 	}
 
-	root = get_default_root(s, subvol_objectid);
-	if (IS_ERR(root)) {
-		error = PTR_ERR(root);
-		deactivate_locked_super(s);
-		goto error_free_subvol_name;
-	}
 	/* if they gave us a subvolume name bind mount into that */
 	if (strcmp(subvol_name, ".")) {
 		struct dentry *new_root;
+
+		root = get_default_root(s, subvol_rootid);
+		if (IS_ERR(root)) {
+			error = PTR_ERR(root);
+			deactivate_locked_super(s);
+			goto error_free_subvol_name;
+		}
+
 		mutex_lock(&root->d_inode->i_mutex);
 		new_root = lookup_one_len(subvol_name, root,
 				      strlen(subvol_name));
@@ -816,6 +833,14 @@ static int btrfs_get_sb(struct file_system_type *fs_type,
int flags,
 		dput(root);
 		root = new_root;
 	}
+	} else {
+		root = get_default_root(s, subvol_objectid);
+		if (IS_ERR(root)) {
+			error = PTR_ERR(root);
+			deactivate_locked_super(s);
+			goto error_free_subvol_name;
+		}
+	}
 
 	mnt->mnt_sb = s;
 	mnt->mnt_root = root;
-- 
1.7.0.4

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Zhong, Xin

2011-Apr-06 08:10 UTC

head link

RE: [PATCH V2] Btrfs: fix subvolume mount by name problem when default mount subvolume is set

> -----Original Message-----
> From: linux-btrfs-owner@vger.kernel.org [mailto:linux-btrfs-
> owner@vger.kernel.org] On Behalf Of Li Zefan
> Sent: Wednesday, April 06, 2011 2:34 PM
> To: Zhong, Xin
> Cc: linux-btrfs@vger.kernel.org
> Subject: Re: [PATCH V2] Btrfs: fix subvolume mount by name problem when
> default mount subvolume is set
> 
> 13:27, Zhong, Xin wrote:
> > We create two subvolumes (meego_root and meego_home) in
> > btrfs root directory. And set meego_root as default mount
> > subvolume. After we remount btrfs, meego_root is mounted
> > to top directory by default. Then when we try to mount
> > meego_home (subvol=meego_home) to a subdirectory, it failed.
> > The problem is when default mount subvolume is set to
> > meego_root, we search meego_home in meego_root but can not find
> > it. So the solution is to add a new mount option (subvolrootid)
> > to specify subvol id of root and search subvol name in it. For
> > our case, now we can use "-o subvolrootid=0,subvol=meego_home)
> > to mount meego_home.
> >
> > Detail information can be found in meego bugzilla:
> > https://bugs.meego.com/show_bug.cgi?id=15055
> >
> > Signed-off-by: Zhong, Xin <xin.zhong@intel.com>
> > ---
> >  fs/btrfs/super.c |   43 ++++++++++++++++++++++++++++++++++---------
> >  1 files changed, 34 insertions(+), 9 deletions(-)
> >
> 
> I guess you forgot to run checkpatch.pl.
Sorry for my mistake. I have fixed it and resubmit. Thanks!
> 
> ERROR: trailing whitespace
> #183: FILE: fs/btrfs/super.c:807:
> +^I^I$
> 
> ERROR: else should follow close brace '}'
> #198: FILE: fs/btrfs/super.c:836:
>         }
> +       else {
> 
> total: 2 errors, 0 warnings, 100 lines checked
> --
> To unsubscribe from this list: send the line "unsubscribe
linux-btrfs"
> in
> the body of a message to majordomo@vger.kernel.org
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