new helpers: lock_mount_hash/unlock_mount_hash
aka br_write_{lock,unlock} of vfsmount_lock. Inlines in fs/mount.h,
vfsmount_lock extern moved over there as well.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
Родитель
aab407fc5c
Коммит
719ea2fbb5
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@ -26,6 +26,7 @@
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#include <linux/blkdev.h>
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#include <linux/backing-dev.h>
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#include <linux/tracepoint.h>
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#include <linux/device.h>
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#include "internal.h"
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/*
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@ -9,8 +9,6 @@
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/lglock.h>
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struct super_block;
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struct file_system_type;
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struct linux_binprm;
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@ -62,8 +60,6 @@ extern int sb_prepare_remount_readonly(struct super_block *);
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extern void __init mnt_init(void);
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extern struct lglock vfsmount_lock;
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extern int __mnt_want_write(struct vfsmount *);
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extern int __mnt_want_write_file(struct file *);
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extern void __mnt_drop_write(struct vfsmount *);
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13
fs/mount.h
13
fs/mount.h
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@ -1,6 +1,7 @@
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#include <linux/mount.h>
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#include <linux/seq_file.h>
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#include <linux/poll.h>
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#include <linux/lglock.h>
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struct mnt_namespace {
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atomic_t count;
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@ -83,6 +84,18 @@ static inline void get_mnt_ns(struct mnt_namespace *ns)
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atomic_inc(&ns->count);
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}
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extern struct lglock vfsmount_lock;
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static inline void lock_mount_hash(void)
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{
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br_write_lock(&vfsmount_lock);
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}
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static inline void unlock_mount_hash(void)
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{
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br_write_unlock(&vfsmount_lock);
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}
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struct proc_mounts {
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struct seq_file m;
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struct mnt_namespace *ns;
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@ -456,7 +456,7 @@ static int mnt_make_readonly(struct mount *mnt)
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{
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int ret = 0;
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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mnt->mnt.mnt_flags |= MNT_WRITE_HOLD;
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/*
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* After storing MNT_WRITE_HOLD, we'll read the counters. This store
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@ -490,15 +490,15 @@ static int mnt_make_readonly(struct mount *mnt)
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*/
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smp_wmb();
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mnt->mnt.mnt_flags &= ~MNT_WRITE_HOLD;
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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return ret;
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}
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static void __mnt_unmake_readonly(struct mount *mnt)
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{
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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mnt->mnt.mnt_flags &= ~MNT_READONLY;
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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}
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int sb_prepare_remount_readonly(struct super_block *sb)
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@ -510,7 +510,7 @@ int sb_prepare_remount_readonly(struct super_block *sb)
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if (atomic_long_read(&sb->s_remove_count))
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return -EBUSY;
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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list_for_each_entry(mnt, &sb->s_mounts, mnt_instance) {
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if (!(mnt->mnt.mnt_flags & MNT_READONLY)) {
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mnt->mnt.mnt_flags |= MNT_WRITE_HOLD;
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@ -532,7 +532,7 @@ int sb_prepare_remount_readonly(struct super_block *sb)
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if (mnt->mnt.mnt_flags & MNT_WRITE_HOLD)
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mnt->mnt.mnt_flags &= ~MNT_WRITE_HOLD;
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}
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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return err;
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}
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@ -794,9 +794,9 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void
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mnt->mnt.mnt_sb = root->d_sb;
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mnt->mnt_mountpoint = mnt->mnt.mnt_root;
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mnt->mnt_parent = mnt;
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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list_add_tail(&mnt->mnt_instance, &root->d_sb->s_mounts);
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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return &mnt->mnt;
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}
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EXPORT_SYMBOL_GPL(vfs_kern_mount);
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@ -837,9 +837,9 @@ static struct mount *clone_mnt(struct mount *old, struct dentry *root,
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mnt->mnt.mnt_root = dget(root);
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mnt->mnt_mountpoint = mnt->mnt.mnt_root;
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mnt->mnt_parent = mnt;
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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list_add_tail(&mnt->mnt_instance, &sb->s_mounts);
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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if ((flag & CL_SLAVE) ||
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((flag & CL_SHARED_TO_SLAVE) && IS_MNT_SHARED(old))) {
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@ -883,28 +883,28 @@ put_again:
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}
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br_read_unlock(&vfsmount_lock);
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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mnt_add_count(mnt, -1);
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if (mnt_get_count(mnt)) {
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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return;
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}
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#else
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mnt_add_count(mnt, -1);
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if (likely(mnt_get_count(mnt)))
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return;
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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#endif
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if (unlikely(mnt->mnt_pinned)) {
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mnt_add_count(mnt, mnt->mnt_pinned + 1);
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mnt->mnt_pinned = 0;
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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acct_auto_close_mnt(&mnt->mnt);
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goto put_again;
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}
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list_del(&mnt->mnt_instance);
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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/*
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* This probably indicates that somebody messed
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@ -945,21 +945,21 @@ EXPORT_SYMBOL(mntget);
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void mnt_pin(struct vfsmount *mnt)
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{
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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real_mount(mnt)->mnt_pinned++;
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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}
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EXPORT_SYMBOL(mnt_pin);
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void mnt_unpin(struct vfsmount *m)
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{
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struct mount *mnt = real_mount(m);
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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if (mnt->mnt_pinned) {
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mnt_add_count(mnt, 1);
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mnt->mnt_pinned--;
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}
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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}
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EXPORT_SYMBOL(mnt_unpin);
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@ -1076,12 +1076,12 @@ int may_umount_tree(struct vfsmount *m)
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BUG_ON(!m);
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/* write lock needed for mnt_get_count */
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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for (p = mnt; p; p = next_mnt(p, mnt)) {
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actual_refs += mnt_get_count(p);
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minimum_refs += 2;
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}
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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if (actual_refs > minimum_refs)
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return 0;
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@ -1108,10 +1108,10 @@ int may_umount(struct vfsmount *mnt)
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{
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int ret = 1;
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down_read(&namespace_sem);
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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if (propagate_mount_busy(real_mount(mnt), 2))
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ret = 0;
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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up_read(&namespace_sem);
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return ret;
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}
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@ -1208,12 +1208,12 @@ static int do_umount(struct mount *mnt, int flags)
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* probably don't strictly need the lock here if we examined
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* all race cases, but it's a slowpath.
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*/
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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if (mnt_get_count(mnt) != 2) {
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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return -EBUSY;
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}
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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if (!xchg(&mnt->mnt_expiry_mark, 1))
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return -EAGAIN;
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@ -1255,7 +1255,7 @@ static int do_umount(struct mount *mnt, int flags)
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}
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namespace_lock();
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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event++;
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if (!(flags & MNT_DETACH))
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@ -1267,7 +1267,7 @@ static int do_umount(struct mount *mnt, int flags)
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umount_tree(mnt, 1);
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retval = 0;
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}
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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namespace_unlock();
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return retval;
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}
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@ -1410,18 +1410,18 @@ struct mount *copy_tree(struct mount *mnt, struct dentry *dentry,
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q = clone_mnt(p, p->mnt.mnt_root, flag);
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if (IS_ERR(q))
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goto out;
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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list_add_tail(&q->mnt_list, &res->mnt_list);
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attach_mnt(q, parent, p->mnt_mp);
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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}
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}
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return res;
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out:
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if (res) {
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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umount_tree(res, 0);
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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}
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return q;
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}
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@ -1443,9 +1443,9 @@ struct vfsmount *collect_mounts(struct path *path)
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void drop_collected_mounts(struct vfsmount *mnt)
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{
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namespace_lock();
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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umount_tree(real_mount(mnt), 0);
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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namespace_unlock();
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}
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@ -1572,7 +1572,7 @@ static int attach_recursive_mnt(struct mount *source_mnt,
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if (err)
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goto out_cleanup_ids;
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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if (IS_MNT_SHARED(dest_mnt)) {
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for (p = source_mnt; p; p = next_mnt(p, source_mnt))
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@ -1591,7 +1591,7 @@ static int attach_recursive_mnt(struct mount *source_mnt,
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list_del_init(&child->mnt_hash);
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commit_tree(child);
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}
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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return 0;
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@ -1693,10 +1693,10 @@ static int do_change_type(struct path *path, int flag)
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goto out_unlock;
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}
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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for (m = mnt; m; m = (recurse ? next_mnt(m, mnt) : NULL))
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change_mnt_propagation(m, type);
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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out_unlock:
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namespace_unlock();
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@ -1768,9 +1768,9 @@ static int do_loopback(struct path *path, const char *old_name,
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err = graft_tree(mnt, parent, mp);
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if (err) {
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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umount_tree(mnt, 0);
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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}
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out2:
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unlock_mount(mp);
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@ -1829,11 +1829,11 @@ static int do_remount(struct path *path, int flags, int mnt_flags,
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else
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err = do_remount_sb(sb, flags, data, 0);
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if (!err) {
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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mnt_flags |= mnt->mnt.mnt_flags & MNT_PROPAGATION_MASK;
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mnt->mnt.mnt_flags = mnt_flags;
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touch_mnt_namespace(mnt->mnt_ns);
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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}
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up_write(&sb->s_umount);
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return err;
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@ -2093,7 +2093,7 @@ void mark_mounts_for_expiry(struct list_head *mounts)
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return;
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namespace_lock();
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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/* extract from the expiration list every vfsmount that matches the
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* following criteria:
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@ -2112,7 +2112,7 @@ void mark_mounts_for_expiry(struct list_head *mounts)
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touch_mnt_namespace(mnt->mnt_ns);
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umount_tree(mnt, 1);
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}
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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namespace_unlock();
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}
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@ -2662,7 +2662,7 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root,
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if (!is_path_reachable(old_mnt, old.dentry, &new))
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goto out4;
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root_mp->m_count++; /* pin it so it won't go away */
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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detach_mnt(new_mnt, &parent_path);
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detach_mnt(root_mnt, &root_parent);
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if (root_mnt->mnt.mnt_flags & MNT_LOCKED) {
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@ -2674,7 +2674,7 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root,
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/* mount new_root on / */
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attach_mnt(new_mnt, real_mount(root_parent.mnt), root_mp);
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touch_mnt_namespace(current->nsproxy->mnt_ns);
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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chroot_fs_refs(&root, &new);
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put_mountpoint(root_mp);
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error = 0;
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@ -2784,9 +2784,9 @@ void kern_unmount(struct vfsmount *mnt)
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{
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/* release long term mount so mount point can be released */
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if (!IS_ERR_OR_NULL(mnt)) {
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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real_mount(mnt)->mnt_ns = NULL;
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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mntput(mnt);
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}
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}
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@ -264,12 +264,12 @@ int propagate_mnt(struct mount *dest_mnt, struct mountpoint *dest_mp,
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prev_src_mnt = child;
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}
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out:
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br_write_lock(&vfsmount_lock);
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lock_mount_hash();
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while (!list_empty(&tmp_list)) {
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child = list_first_entry(&tmp_list, struct mount, mnt_hash);
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umount_tree(child, 0);
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}
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br_write_unlock(&vfsmount_lock);
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unlock_mount_hash();
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return ret;
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}
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