Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
setup_mnt(): primitive for connecting a mount to filesystem
Take the identical logics in vfs_create_mount() and clone_mnt() into
a new helper that takes an empty struct mount and attaches it to
given dentry (sub)tree.
Should be called once in the lifetime of every mount, prior to making
it visible in any data structures.
After that point ->mnt_root and ->mnt_sb never change; ->mnt_root
is a counting reference to dentry and ->mnt_sb - an active reference
to superblock.
Mount remains associated with that dentry tree all the way until
the call of cleanup_mnt(), when the refcount eventually drops
to zero.
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
+17
-17
+17
-17
fs/namespace.c
+17
-17
fs/namespace.c
···
1196
1196
touch_mnt_namespace(n);
1197
1197
}
1198
1198
1199
+
static void setup_mnt(struct mount *m, struct dentry *root)
1200
+
{
1201
+
struct super_block *s = root->d_sb;
1202
+
1203
+
atomic_inc(&s->s_active);
1204
+
m->mnt.mnt_sb = s;
1205
+
m->mnt.mnt_root = dget(root);
1206
+
m->mnt_mountpoint = m->mnt.mnt_root;
1207
+
m->mnt_parent = m;
1208
+
1209
+
lock_mount_hash();
1210
+
list_add_tail(&m->mnt_instance, &s->s_mounts);
1211
+
unlock_mount_hash();
1212
+
}
1213
+
1199
1214
/**
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1215
* vfs_create_mount - Create a mount for a configured superblock
1201
1216
* @fc: The configuration context with the superblock attached
···
1234
1219
if (fc->sb_flags & SB_KERNMOUNT)
1235
1220
mnt->mnt.mnt_flags = MNT_INTERNAL;
1236
1221
1237
-
atomic_inc(&fc->root->d_sb->s_active);
1238
-
mnt->mnt.mnt_sb = fc->root->d_sb;
1239
-
mnt->mnt.mnt_root = dget(fc->root);
1240
-
mnt->mnt_mountpoint = mnt->mnt.mnt_root;
1241
-
mnt->mnt_parent = mnt;
1222
+
setup_mnt(mnt, fc->root);
1242
1223
1243
-
lock_mount_hash();
1244
-
list_add_tail(&mnt->mnt_instance, &mnt->mnt.mnt_sb->s_mounts);
1245
-
unlock_mount_hash();
1246
1224
return &mnt->mnt;
1247
1225
}
1248
1226
EXPORT_SYMBOL(vfs_create_mount);
···
1293
1285
static struct mount *clone_mnt(struct mount *old, struct dentry *root,
1294
1286
int flag)
1295
1287
{
1296
-
struct super_block *sb = old->mnt.mnt_sb;
1297
1288
struct mount *mnt;
1298
1289
int err;
1299
1290
···
1317
1310
if (mnt->mnt_group_id)
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1311
set_mnt_shared(mnt);
1319
1312
1320
-
atomic_inc(&sb->s_active);
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1313
mnt->mnt.mnt_idmap = mnt_idmap_get(mnt_idmap(&old->mnt));
1322
1314
1323
-
mnt->mnt.mnt_sb = sb;
1324
-
mnt->mnt.mnt_root = dget(root);
1325
-
mnt->mnt_mountpoint = mnt->mnt.mnt_root;
1326
-
mnt->mnt_parent = mnt;
1327
-
lock_mount_hash();
1328
-
list_add_tail(&mnt->mnt_instance, &sb->s_mounts);
1329
-
unlock_mount_hash();
1315
+
setup_mnt(mnt, root);
1330
1316
1331
1317
if (flag & CL_PRIVATE) // we are done with it
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return mnt;