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Diffstat (limited to 'fs/super.c')
-rw-r--r--fs/super.c240
1 files changed, 64 insertions, 176 deletions
diff --git a/fs/super.c b/fs/super.c
index 786fe7d7279..83b47416d00 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -28,7 +28,6 @@
#include <linux/blkdev.h>
#include <linux/quotaops.h>
#include <linux/namei.h>
-#include <linux/buffer_head.h> /* for fsync_super() */
#include <linux/mount.h>
#include <linux/security.h>
#include <linux/syscalls.h>
@@ -38,7 +37,6 @@
#include <linux/kobject.h>
#include <linux/mutex.h>
#include <linux/file.h>
-#include <linux/async.h>
#include <asm/uaccess.h>
#include "internal.h"
@@ -72,7 +70,6 @@ static struct super_block *alloc_super(struct file_system_type *type)
INIT_HLIST_HEAD(&s->s_anon);
INIT_LIST_HEAD(&s->s_inodes);
INIT_LIST_HEAD(&s->s_dentry_lru);
- INIT_LIST_HEAD(&s->s_async_list);
init_rwsem(&s->s_umount);
mutex_init(&s->s_lock);
lockdep_set_class(&s->s_umount, &type->s_umount_key);
@@ -208,6 +205,34 @@ void deactivate_super(struct super_block *s)
EXPORT_SYMBOL(deactivate_super);
/**
+ * deactivate_locked_super - drop an active reference to superblock
+ * @s: superblock to deactivate
+ *
+ * Equivalent of up_write(&s->s_umount); deactivate_super(s);, except that
+ * it does not unlock it until it's all over. As the result, it's safe to
+ * use to dispose of new superblock on ->get_sb() failure exits - nobody
+ * will see the sucker until it's all over. Equivalent using up_write +
+ * deactivate_super is safe for that purpose only if superblock is either
+ * safe to use or has NULL ->s_root when we unlock.
+ */
+void deactivate_locked_super(struct super_block *s)
+{
+ struct file_system_type *fs = s->s_type;
+ if (atomic_dec_and_lock(&s->s_active, &sb_lock)) {
+ s->s_count -= S_BIAS-1;
+ spin_unlock(&sb_lock);
+ vfs_dq_off(s, 0);
+ fs->kill_sb(s);
+ put_filesystem(fs);
+ put_super(s);
+ } else {
+ up_write(&s->s_umount);
+ }
+}
+
+EXPORT_SYMBOL(deactivate_locked_super);
+
+/**
* grab_super - acquire an active reference
* @s: reference we are trying to make active
*
@@ -257,38 +282,6 @@ void unlock_super(struct super_block * sb)
EXPORT_SYMBOL(lock_super);
EXPORT_SYMBOL(unlock_super);
-/*
- * Write out and wait upon all dirty data associated with this
- * superblock. Filesystem data as well as the underlying block
- * device. Takes the superblock lock. Requires a second blkdev
- * flush by the caller to complete the operation.
- */
-void __fsync_super(struct super_block *sb)
-{
- sync_inodes_sb(sb, 0);
- vfs_dq_sync(sb);
- lock_super(sb);
- if (sb->s_dirt && sb->s_op->write_super)
- sb->s_op->write_super(sb);
- unlock_super(sb);
- if (sb->s_op->sync_fs)
- sb->s_op->sync_fs(sb, 1);
- sync_blockdev(sb->s_bdev);
- sync_inodes_sb(sb, 1);
-}
-
-/*
- * Write out and wait upon all dirty data associated with this
- * superblock. Filesystem data as well as the underlying block
- * device. Takes the superblock lock.
- */
-int fsync_super(struct super_block *sb)
-{
- __fsync_super(sb);
- return sync_blockdev(sb->s_bdev);
-}
-EXPORT_SYMBOL_GPL(fsync_super);
-
/**
* generic_shutdown_super - common helper for ->kill_sb()
* @sb: superblock to kill
@@ -310,21 +303,13 @@ void generic_shutdown_super(struct super_block *sb)
if (sb->s_root) {
shrink_dcache_for_umount(sb);
- fsync_super(sb);
- lock_super(sb);
+ sync_filesystem(sb);
+ get_fs_excl();
sb->s_flags &= ~MS_ACTIVE;
- /*
- * wait for asynchronous fs operations to finish before going further
- */
- async_synchronize_full_domain(&sb->s_async_list);
-
/* bad name - it should be evict_inodes() */
invalidate_inodes(sb);
- lock_kernel();
- if (sop->write_super && sb->s_dirt)
- sop->write_super(sb);
if (sop->put_super)
sop->put_super(sb);
@@ -334,9 +319,7 @@ void generic_shutdown_super(struct super_block *sb)
"Self-destruct in 5 seconds. Have a nice day...\n",
sb->s_id);
}
-
- unlock_kernel();
- unlock_super(sb);
+ put_fs_excl();
}
spin_lock(&sb_lock);
/* should be initialized for __put_super_and_need_restart() */
@@ -413,16 +396,14 @@ void drop_super(struct super_block *sb)
EXPORT_SYMBOL(drop_super);
-static inline void write_super(struct super_block *sb)
-{
- lock_super(sb);
- if (sb->s_root && sb->s_dirt)
- if (sb->s_op->write_super)
- sb->s_op->write_super(sb);
- unlock_super(sb);
-}
-
-/*
+/**
+ * sync_supers - helper for periodic superblock writeback
+ *
+ * Call the write_super method if present on all dirty superblocks in
+ * the system. This is for the periodic writeback used by most older
+ * filesystems. For data integrity superblock writeback use
+ * sync_filesystems() instead.
+ *
* Note: check the dirty flag before waiting, so we don't
* hold up the sync while mounting a device. (The newly
* mounted device won't need syncing.)
@@ -434,12 +415,15 @@ void sync_supers(void)
spin_lock(&sb_lock);
restart:
list_for_each_entry(sb, &super_blocks, s_list) {
- if (sb->s_dirt) {
+ if (sb->s_op->write_super && sb->s_dirt) {
sb->s_count++;
spin_unlock(&sb_lock);
+
down_read(&sb->s_umount);
- write_super(sb);
+ if (sb->s_root && sb->s_dirt)
+ sb->s_op->write_super(sb);
up_read(&sb->s_umount);
+
spin_lock(&sb_lock);
if (__put_super_and_need_restart(sb))
goto restart;
@@ -448,60 +432,6 @@ restart:
spin_unlock(&sb_lock);
}
-/*
- * Call the ->sync_fs super_op against all filesystems which are r/w and
- * which implement it.
- *
- * This operation is careful to avoid the livelock which could easily happen
- * if two or more filesystems are being continuously dirtied. s_need_sync_fs
- * is used only here. We set it against all filesystems and then clear it as
- * we sync them. So redirtied filesystems are skipped.
- *
- * But if process A is currently running sync_filesystems and then process B
- * calls sync_filesystems as well, process B will set all the s_need_sync_fs
- * flags again, which will cause process A to resync everything. Fix that with
- * a local mutex.
- *
- * (Fabian) Avoid sync_fs with clean fs & wait mode 0
- */
-void sync_filesystems(int wait)
-{
- struct super_block *sb;
- static DEFINE_MUTEX(mutex);
-
- mutex_lock(&mutex); /* Could be down_interruptible */
- spin_lock(&sb_lock);
- list_for_each_entry(sb, &super_blocks, s_list) {
- if (!sb->s_op->sync_fs)
- continue;
- if (sb->s_flags & MS_RDONLY)
- continue;
- sb->s_need_sync_fs = 1;
- }
-
-restart:
- list_for_each_entry(sb, &super_blocks, s_list) {
- if (!sb->s_need_sync_fs)
- continue;
- sb->s_need_sync_fs = 0;
- if (sb->s_flags & MS_RDONLY)
- continue; /* hm. Was remounted r/o meanwhile */
- sb->s_count++;
- spin_unlock(&sb_lock);
- down_read(&sb->s_umount);
- async_synchronize_full_domain(&sb->s_async_list);
- if (sb->s_root && (wait || sb->s_dirt))
- sb->s_op->sync_fs(sb, wait);
- up_read(&sb->s_umount);
- /* restart only when sb is no longer on the list */
- spin_lock(&sb_lock);
- if (__put_super_and_need_restart(sb))
- goto restart;
- }
- spin_unlock(&sb_lock);
- mutex_unlock(&mutex);
-}
-
/**
* get_super - get the superblock of a device
* @bdev: device to get the superblock for
@@ -588,45 +518,6 @@ out:
}
/**
- * mark_files_ro - mark all files read-only
- * @sb: superblock in question
- *
- * All files are marked read-only. We don't care about pending
- * delete files so this should be used in 'force' mode only.
- */
-
-static void mark_files_ro(struct super_block *sb)
-{
- struct file *f;
-
-retry:
- file_list_lock();
- list_for_each_entry(f, &sb->s_files, f_u.fu_list) {
- struct vfsmount *mnt;
- if (!S_ISREG(f->f_path.dentry->d_inode->i_mode))
- continue;
- if (!file_count(f))
- continue;
- if (!(f->f_mode & FMODE_WRITE))
- continue;
- f->f_mode &= ~FMODE_WRITE;
- if (file_check_writeable(f) != 0)
- continue;
- file_release_write(f);
- mnt = mntget(f->f_path.mnt);
- file_list_unlock();
- /*
- * This can sleep, so we can't hold
- * the file_list_lock() spinlock.
- */
- mnt_drop_write(mnt);
- mntput(mnt);
- goto retry;
- }
- file_list_unlock();
-}
-
-/**
* do_remount_sb - asks filesystem to change mount options.
* @sb: superblock in question
* @flags: numeric part of options
@@ -647,27 +538,31 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
if (flags & MS_RDONLY)
acct_auto_close(sb);
shrink_dcache_sb(sb);
- fsync_super(sb);
+ sync_filesystem(sb);
/* If we are remounting RDONLY and current sb is read/write,
make sure there are no rw files opened */
if ((flags & MS_RDONLY) && !(sb->s_flags & MS_RDONLY)) {
if (force)
mark_files_ro(sb);
- else if (!fs_may_remount_ro(sb))
+ else if (!fs_may_remount_ro(sb)) {
+ unlock_kernel();
return -EBUSY;
+ }
retval = vfs_dq_off(sb, 1);
- if (retval < 0 && retval != -ENOSYS)
+ if (retval < 0 && retval != -ENOSYS) {
+ unlock_kernel();
return -EBUSY;
+ }
}
remount_rw = !(flags & MS_RDONLY) && (sb->s_flags & MS_RDONLY);
if (sb->s_op->remount_fs) {
- lock_super(sb);
retval = sb->s_op->remount_fs(sb, &flags, data);
- unlock_super(sb);
- if (retval)
+ if (retval) {
+ unlock_kernel();
return retval;
+ }
}
sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
if (remount_rw)
@@ -683,18 +578,17 @@ static void do_emergency_remount(struct work_struct *work)
list_for_each_entry(sb, &super_blocks, s_list) {
sb->s_count++;
spin_unlock(&sb_lock);
- down_read(&sb->s_umount);
+ down_write(&sb->s_umount);
if (sb->s_root && sb->s_bdev && !(sb->s_flags & MS_RDONLY)) {
/*
* ->remount_fs needs lock_kernel().
*
* What lock protects sb->s_flags??
*/
- lock_kernel();
do_remount_sb(sb, MS_RDONLY, NULL, 1);
- unlock_kernel();
}
- drop_super(sb);
+ up_write(&sb->s_umount);
+ put_super(sb);
spin_lock(&sb_lock);
}
spin_unlock(&sb_lock);
@@ -797,8 +691,7 @@ int get_sb_ns(struct file_system_type *fs_type, int flags, void *data,
sb->s_flags = flags;
err = fill_super(sb, data, flags & MS_SILENT ? 1 : 0);
if (err) {
- up_write(&sb->s_umount);
- deactivate_super(sb);
+ deactivate_locked_super(sb);
return err;
}
@@ -854,8 +747,7 @@ int get_sb_bdev(struct file_system_type *fs_type,
if (s->s_root) {
if ((flags ^ s->s_flags) & MS_RDONLY) {
- up_write(&s->s_umount);
- deactivate_super(s);
+ deactivate_locked_super(s);
error = -EBUSY;
goto error_bdev;
}
@@ -870,8 +762,7 @@ int get_sb_bdev(struct file_system_type *fs_type,
sb_set_blocksize(s, block_size(bdev));
error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
if (error) {
- up_write(&s->s_umount);
- deactivate_super(s);
+ deactivate_locked_super(s);
goto error;
}
@@ -897,7 +788,7 @@ void kill_block_super(struct super_block *sb)
struct block_device *bdev = sb->s_bdev;
fmode_t mode = sb->s_mode;
- bdev->bd_super = 0;
+ bdev->bd_super = NULL;
generic_shutdown_super(sb);
sync_blockdev(bdev);
close_bdev_exclusive(bdev, mode);
@@ -921,8 +812,7 @@ int get_sb_nodev(struct file_system_type *fs_type,
error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
if (error) {
- up_write(&s->s_umount);
- deactivate_super(s);
+ deactivate_locked_super(s);
return error;
}
s->s_flags |= MS_ACTIVE;
@@ -952,8 +842,7 @@ int get_sb_single(struct file_system_type *fs_type,
s->s_flags = flags;
error = fill_super(s, data, flags & MS_SILENT ? 1 : 0);
if (error) {
- up_write(&s->s_umount);
- deactivate_super(s);
+ deactivate_locked_super(s);
return error;
}
s->s_flags |= MS_ACTIVE;
@@ -1006,8 +895,7 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void
return mnt;
out_sb:
dput(mnt->mnt_root);
- up_write(&mnt->mnt_sb->s_umount);
- deactivate_super(mnt->mnt_sb);
+ deactivate_locked_super(mnt->mnt_sb);
out_free_secdata:
free_secdata(secdata);
out_mnt: