[PATCH 43/43] afs: Use fs_context to pass parameters over automount
David Howells
dhowells at redhat.com
Tue Feb 19 16:34:26 UTC 2019
Alter the AFS automounting code to create and modify an fs_context struct
when parameterising a new mount triggered by an AFS mountpoint rather than
constructing device name and option strings.
Also remove the cell=, vol= and rwpath options as they are then redundant.
The reason they existed is because the 'device name' may be derived
literally from a mountpoint object in the filesystem, so default cell and
parent-type information needed to be passed in by some other method from
the automount routines. The vol= option didn't end up being used.
Signed-off-by: David Howells <dhowells at redhat.com>
cc: Eric W. Biederman <ebiederm at redhat.com>
Signed-off-by: Al Viro <viro at zeniv.linux.org.uk>
---
fs/afs/internal.h | 1
fs/afs/mntpt.c | 148 ++++++++++++++++++++++++++++-------------------------
fs/afs/super.c | 40 +-------------
3 files changed, 80 insertions(+), 109 deletions(-)
diff --git a/fs/afs/internal.h b/fs/afs/internal.h
index 3ed0550a2e29..bb1f244b2b3a 100644
--- a/fs/afs/internal.h
+++ b/fs/afs/internal.h
@@ -37,7 +37,6 @@ struct pagevec;
struct afs_call;
struct afs_fs_context {
- bool rwpath; /* T if the parent should be considered R/W */
bool force; /* T to force cell type */
bool autocell; /* T if set auto mount operation */
bool dyn_root; /* T if dynamic root */
diff --git a/fs/afs/mntpt.c b/fs/afs/mntpt.c
index b3f41d27590b..eecd8b699186 100644
--- a/fs/afs/mntpt.c
+++ b/fs/afs/mntpt.c
@@ -48,6 +48,8 @@ static DECLARE_DELAYED_WORK(afs_mntpt_expiry_timer, afs_mntpt_expiry_timed_out);
static unsigned long afs_mntpt_expiry_timeout = 10 * 60;
+static const char afs_root_volume[] = "root.cell";
+
/*
* no valid lookup procedure on this sort of dir
*/
@@ -69,108 +71,112 @@ static int afs_mntpt_open(struct inode *inode, struct file *file)
}
/*
- * create a vfsmount to be automounted
+ * Set the parameters for the proposed superblock.
*/
-static struct vfsmount *afs_mntpt_do_automount(struct dentry *mntpt)
+static int afs_mntpt_set_params(struct fs_context *fc, struct dentry *mntpt)
{
- struct afs_super_info *as;
- struct vfsmount *mnt;
- struct afs_vnode *vnode;
- struct page *page;
- char *devname, *options;
- bool rwpath = false;
+ struct afs_fs_context *ctx = fc->fs_private;
+ struct afs_super_info *src_as = AFS_FS_S(mntpt->d_sb);
+ struct afs_vnode *vnode = AFS_FS_I(d_inode(mntpt));
+ struct afs_cell *cell;
+ const char *p;
int ret;
- _enter("{%pd}", mntpt);
-
- BUG_ON(!d_inode(mntpt));
-
- ret = -ENOMEM;
- devname = (char *) get_zeroed_page(GFP_KERNEL);
- if (!devname)
- goto error_no_devname;
-
- options = (char *) get_zeroed_page(GFP_KERNEL);
- if (!options)
- goto error_no_options;
+ if (fc->net_ns != src_as->net_ns) {
+ put_net(fc->net_ns);
+ fc->net_ns = get_net(src_as->net_ns);
+ }
- vnode = AFS_FS_I(d_inode(mntpt));
+ if (src_as->volume && src_as->volume->type == AFSVL_RWVOL) {
+ ctx->type = AFSVL_RWVOL;
+ ctx->force = true;
+ }
+ if (ctx->cell) {
+ afs_put_cell(ctx->net, ctx->cell);
+ ctx->cell = NULL;
+ }
if (test_bit(AFS_VNODE_PSEUDODIR, &vnode->flags)) {
/* if the directory is a pseudo directory, use the d_name */
- static const char afs_root_cell[] = ":root.cell.";
unsigned size = mntpt->d_name.len;
- ret = -ENOENT;
- if (size < 2 || size > AFS_MAXCELLNAME)
- goto error_no_page;
+ if (size < 2)
+ return -ENOENT;
+ p = mntpt->d_name.name;
if (mntpt->d_name.name[0] == '.') {
- devname[0] = '%';
- memcpy(devname + 1, mntpt->d_name.name + 1, size - 1);
- memcpy(devname + size, afs_root_cell,
- sizeof(afs_root_cell));
- rwpath = true;
- } else {
- devname[0] = '#';
- memcpy(devname + 1, mntpt->d_name.name, size);
- memcpy(devname + size + 1, afs_root_cell,
- sizeof(afs_root_cell));
+ size--;
+ p++;
+ ctx->type = AFSVL_RWVOL;
+ ctx->force = true;
}
+ if (size > AFS_MAXCELLNAME)
+ return -ENAMETOOLONG;
+
+ cell = afs_lookup_cell(ctx->net, p, size, NULL, false);
+ if (IS_ERR(cell)) {
+ pr_err("kAFS: unable to lookup cell '%pd'\n", mntpt);
+ return PTR_ERR(cell);
+ }
+ ctx->cell = cell;
+
+ ctx->volname = afs_root_volume;
+ ctx->volnamesz = sizeof(afs_root_volume) - 1;
} else {
/* read the contents of the AFS special symlink */
+ struct page *page;
loff_t size = i_size_read(d_inode(mntpt));
char *buf;
- ret = -EINVAL;
+ if (src_as->cell)
+ ctx->cell = afs_get_cell(src_as->cell);
+
if (size > PAGE_SIZE - 1)
- goto error_no_page;
+ return -EINVAL;
page = read_mapping_page(d_inode(mntpt)->i_mapping, 0, NULL);
- if (IS_ERR(page)) {
- ret = PTR_ERR(page);
- goto error_no_page;
- }
+ if (IS_ERR(page))
+ return PTR_ERR(page);
if (PageError(page)) {
ret = afs_bad(AFS_FS_I(d_inode(mntpt)), afs_file_error_mntpt);
- goto error;
+ put_page(page);
+ return ret;
}
- buf = kmap_atomic(page);
- memcpy(devname, buf, size);
- kunmap_atomic(buf);
+ buf = kmap(page);
+ ret = vfs_parse_fs_string(fc, "source", buf, size);
+ kunmap(page);
put_page(page);
- page = NULL;
+ if (ret < 0)
+ return ret;
}
- /* work out what options we want */
- as = AFS_FS_S(mntpt->d_sb);
- if (as->cell) {
- memcpy(options, "cell=", 5);
- strcpy(options + 5, as->cell->name);
- if ((as->volume && as->volume->type == AFSVL_RWVOL) || rwpath)
- strcat(options, ",rwpath");
- }
+ return 0;
+}
- /* try and do the mount */
- _debug("--- attempting mount %s -o %s ---", devname, options);
- mnt = vfs_submount(mntpt, &afs_fs_type, devname, options);
- _debug("--- mount result %p ---", mnt);
+/*
+ * create a vfsmount to be automounted
+ */
+static struct vfsmount *afs_mntpt_do_automount(struct dentry *mntpt)
+{
+ struct fs_context *fc;
+ struct vfsmount *mnt;
+ int ret;
- free_page((unsigned long) devname);
- free_page((unsigned long) options);
- _leave(" = %p", mnt);
- return mnt;
+ BUG_ON(!d_inode(mntpt));
-error:
- put_page(page);
-error_no_page:
- free_page((unsigned long) options);
-error_no_options:
- free_page((unsigned long) devname);
-error_no_devname:
- _leave(" = %d", ret);
- return ERR_PTR(ret);
+ fc = fs_context_for_submount(&afs_fs_type, mntpt);
+ if (IS_ERR(fc))
+ return ERR_CAST(fc);
+
+ ret = afs_mntpt_set_params(fc, mntpt);
+ if (!ret)
+ mnt = fc_mount(fc);
+ else
+ mnt = ERR_PTR(ret);
+
+ put_fs_context(fc);
+ return mnt;
}
/*
diff --git a/fs/afs/super.c b/fs/afs/super.c
index e1a7a8085262..a07af1ab488d 100644
--- a/fs/afs/super.c
+++ b/fs/afs/super.c
@@ -66,20 +66,14 @@ static atomic_t afs_count_active_inodes;
enum afs_param {
Opt_autocell,
- Opt_cell,
Opt_dyn,
- Opt_rwpath,
Opt_source,
- Opt_vol,
};
static const struct fs_parameter_spec afs_param_specs[] = {
fsparam_flag ("autocell", Opt_autocell),
- fsparam_string("cell", Opt_cell),
fsparam_flag ("dyn", Opt_dyn),
- fsparam_flag ("rwpath", Opt_rwpath),
fsparam_string("source", Opt_source),
- fsparam_string("vol", Opt_vol),
{}
};
@@ -202,8 +196,8 @@ static int afs_show_options(struct seq_file *m, struct dentry *root)
*
* This can be one of the following:
* "%[cell:]volume[.]" R/W volume
- * "#[cell:]volume[.]" R/O or R/W volume (rwpath=0),
- * or R/W (rwpath=1) volume
+ * "#[cell:]volume[.]" R/O or R/W volume (R/O parent),
+ * or R/W (R/W parent) volume
* "%[cell:]volume.readonly" R/O volume
* "#[cell:]volume.readonly" R/O volume
* "%[cell:]volume.backup" Backup volume
@@ -234,9 +228,7 @@ static int afs_parse_source(struct fs_context *fc, struct fs_parameter *param)
}
/* determine the type of volume we're looking for */
- ctx->type = AFSVL_ROVOL;
- ctx->force = false;
- if (ctx->rwpath || name[0] == '%') {
+ if (name[0] == '%') {
ctx->type = AFSVL_RWVOL;
ctx->force = true;
}
@@ -305,7 +297,6 @@ static int afs_parse_param(struct fs_context *fc, struct fs_parameter *param)
{
struct fs_parse_result result;
struct afs_fs_context *ctx = fc->fs_private;
- struct afs_cell *cell;
int opt;
opt = fs_parse(fc, &afs_fs_parameters, param, &result);
@@ -313,21 +304,6 @@ static int afs_parse_param(struct fs_context *fc, struct fs_parameter *param)
return opt;
switch (opt) {
- case Opt_cell:
- if (param->size <= 0)
- return -EINVAL;
- if (param->size > AFS_MAXCELLNAME)
- return -ENAMETOOLONG;
-
- rcu_read_lock();
- cell = afs_lookup_cell_rcu(ctx->net, param->string, param->size);
- rcu_read_unlock();
- if (IS_ERR(cell))
- return PTR_ERR(cell);
- afs_put_cell(ctx->net, ctx->cell);
- ctx->cell = cell;
- break;
-
case Opt_source:
return afs_parse_source(fc, param);
@@ -339,13 +315,6 @@ static int afs_parse_param(struct fs_context *fc, struct fs_parameter *param)
ctx->dyn_root = true;
break;
- case Opt_rwpath:
- ctx->rwpath = true;
- break;
-
- case Opt_vol:
- return invalf(fc, "'vol' param is obsolete");
-
default:
return -EINVAL;
}
@@ -616,9 +585,6 @@ static int afs_init_fs_context(struct fs_context *fc)
struct afs_fs_context *ctx;
struct afs_cell *cell;
- if (current->nsproxy->net_ns != &init_net)
- return -EINVAL;
-
ctx = kzalloc(sizeof(struct afs_fs_context), GFP_KERNEL);
if (!ctx)
return -ENOMEM;
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