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Diffstat (limited to 'fs/nilfs2/super.c')
-rw-r--r--fs/nilfs2/super.c256
1 files changed, 93 insertions, 163 deletions
diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index 6989b03..1777a34 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -65,9 +65,8 @@ MODULE_DESCRIPTION("A New Implementation of the Log-structured Filesystem "
"(NILFS)");
MODULE_LICENSE("GPL");
+static void nilfs_write_super(struct super_block *sb);
static int nilfs_remount(struct super_block *sb, int *flags, char *data);
-static int test_exclusive_mount(struct file_system_type *fs_type,
- struct block_device *bdev, int flags);
/**
* nilfs_error() - report failure condition on a filesystem
@@ -315,6 +314,11 @@ static void nilfs_put_super(struct super_block *sb)
struct nilfs_sb_info *sbi = NILFS_SB(sb);
struct the_nilfs *nilfs = sbi->s_nilfs;
+ lock_kernel();
+
+ if (sb->s_dirt)
+ nilfs_write_super(sb);
+
nilfs_detach_segment_constructor(sbi);
if (!(sb->s_flags & MS_RDONLY)) {
@@ -323,12 +327,18 @@ static void nilfs_put_super(struct super_block *sb)
nilfs_commit_super(sbi, 1);
up_write(&nilfs->ns_sem);
}
+ down_write(&nilfs->ns_super_sem);
+ if (nilfs->ns_current == sbi)
+ nilfs->ns_current = NULL;
+ up_write(&nilfs->ns_super_sem);
nilfs_detach_checkpoint(sbi);
put_nilfs(sbi->s_nilfs);
sbi->s_super = NULL;
sb->s_fs_info = NULL;
- kfree(sbi);
+ nilfs_put_sbinfo(sbi);
+
+ unlock_kernel();
}
/**
@@ -383,6 +393,8 @@ static int nilfs_sync_fs(struct super_block *sb, int wait)
{
int err = 0;
+ nilfs_write_super(sb);
+
/* This function is called when super block should be written back */
if (wait)
err = nilfs_construct_segment(sb);
@@ -396,9 +408,9 @@ int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno)
struct buffer_head *bh_cp;
int err;
- down_write(&nilfs->ns_sem);
+ down_write(&nilfs->ns_super_sem);
list_add(&sbi->s_list, &nilfs->ns_supers);
- up_write(&nilfs->ns_sem);
+ up_write(&nilfs->ns_super_sem);
sbi->s_ifile = nilfs_mdt_new(
nilfs, sbi->s_super, NILFS_IFILE_INO, NILFS_IFILE_GFP);
@@ -436,9 +448,9 @@ int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno)
nilfs_mdt_destroy(sbi->s_ifile);
sbi->s_ifile = NULL;
- down_write(&nilfs->ns_sem);
+ down_write(&nilfs->ns_super_sem);
list_del_init(&sbi->s_list);
- up_write(&nilfs->ns_sem);
+ up_write(&nilfs->ns_super_sem);
return err;
}
@@ -450,9 +462,9 @@ void nilfs_detach_checkpoint(struct nilfs_sb_info *sbi)
nilfs_mdt_clear(sbi->s_ifile);
nilfs_mdt_destroy(sbi->s_ifile);
sbi->s_ifile = NULL;
- down_write(&nilfs->ns_sem);
+ down_write(&nilfs->ns_super_sem);
list_del_init(&sbi->s_list);
- up_write(&nilfs->ns_sem);
+ up_write(&nilfs->ns_super_sem);
}
static int nilfs_mark_recovery_complete(struct nilfs_sb_info *sbi)
@@ -752,7 +764,7 @@ int nilfs_store_magic_and_option(struct super_block *sb,
* @silent: silent mode flag
* @nilfs: the_nilfs struct
*
- * This function is called exclusively by bd_mount_mutex.
+ * This function is called exclusively by nilfs->ns_mount_mutex.
* So, the recovery process is protected from other simultaneous mounts.
*/
static int
@@ -773,6 +785,7 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent,
get_nilfs(nilfs);
sbi->s_nilfs = nilfs;
sbi->s_super = sb;
+ atomic_set(&sbi->s_count, 1);
err = init_nilfs(nilfs, sbi, (char *)data);
if (err)
@@ -870,6 +883,11 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent,
goto failed_root;
}
+ down_write(&nilfs->ns_super_sem);
+ if (!nilfs_test_opt(sbi, SNAPSHOT))
+ nilfs->ns_current = sbi;
+ up_write(&nilfs->ns_super_sem);
+
return 0;
failed_root:
@@ -885,7 +903,7 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent,
failed_sbi:
put_nilfs(nilfs);
sb->s_fs_info = NULL;
- kfree(sbi);
+ nilfs_put_sbinfo(sbi);
return err;
}
@@ -898,6 +916,9 @@ static int nilfs_remount(struct super_block *sb, int *flags, char *data)
struct nilfs_mount_options old_opts;
int err;
+ lock_kernel();
+
+ down_write(&nilfs->ns_super_sem);
old_sb_flags = sb->s_flags;
old_opts.mount_opt = sbi->s_mount_opt;
old_opts.snapshot_cno = sbi->s_snapshot_cno;
@@ -945,14 +966,12 @@ static int nilfs_remount(struct super_block *sb, int *flags, char *data)
* store the current valid flag. (It may have been changed
* by fsck since we originally mounted the partition.)
*/
- down(&sb->s_bdev->bd_mount_sem);
- /* Check existing RW-mount */
- if (test_exclusive_mount(sb->s_type, sb->s_bdev, 0)) {
+ if (nilfs->ns_current && nilfs->ns_current != sbi) {
printk(KERN_WARNING "NILFS (device %s): couldn't "
- "remount because a RW-mount exists.\n",
+ "remount because an RW-mount exists.\n",
sb->s_id);
err = -EBUSY;
- goto rw_remount_failed;
+ goto restore_opts;
}
if (sbi->s_snapshot_cno != nilfs_last_cno(nilfs)) {
printk(KERN_WARNING "NILFS (device %s): couldn't "
@@ -960,7 +979,7 @@ static int nilfs_remount(struct super_block *sb, int *flags, char *data)
"the latest one.\n",
sb->s_id);
err = -EINVAL;
- goto rw_remount_failed;
+ goto restore_opts;
}
sb->s_flags &= ~MS_RDONLY;
nilfs_clear_opt(sbi, SNAPSHOT);
@@ -968,28 +987,31 @@ static int nilfs_remount(struct super_block *sb, int *flags, char *data)
err = nilfs_attach_segment_constructor(sbi);
if (err)
- goto rw_remount_failed;
+ goto restore_opts;
down_write(&nilfs->ns_sem);
nilfs_setup_super(sbi);
up_write(&nilfs->ns_sem);
- up(&sb->s_bdev->bd_mount_sem);
+ nilfs->ns_current = sbi;
}
out:
+ up_write(&nilfs->ns_super_sem);
+ unlock_kernel();
return 0;
- rw_remount_failed:
- up(&sb->s_bdev->bd_mount_sem);
restore_opts:
sb->s_flags = old_sb_flags;
sbi->s_mount_opt = old_opts.mount_opt;
sbi->s_snapshot_cno = old_opts.snapshot_cno;
+ up_write(&nilfs->ns_super_sem);
+ unlock_kernel();
return err;
}
struct nilfs_super_data {
struct block_device *bdev;
+ struct nilfs_sb_info *sbi;
__u64 cno;
int flags;
};
@@ -1048,33 +1070,7 @@ static int nilfs_test_bdev_super(struct super_block *s, void *data)
{
struct nilfs_super_data *sd = data;
- return s->s_bdev == sd->bdev;
-}
-
-static int nilfs_test_bdev_super2(struct super_block *s, void *data)
-{
- struct nilfs_super_data *sd = data;
- int ret;
-
- if (s->s_bdev != sd->bdev)
- return 0;
-
- if (!((s->s_flags | sd->flags) & MS_RDONLY))
- return 1; /* Reuse an old R/W-mode super_block */
-
- if (s->s_flags & sd->flags & MS_RDONLY) {
- if (down_read_trylock(&s->s_umount)) {
- ret = s->s_root &&
- (sd->cno == NILFS_SB(s)->s_snapshot_cno);
- up_read(&s->s_umount);
- /*
- * This path is locked with sb_lock by sget().
- * So, drop_super() causes deadlock.
- */
- return ret;
- }
- }
- return 0;
+ return sd->sbi && s->s_fs_info == (void *)sd->sbi;
}
static int
@@ -1082,8 +1078,8 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags,
const char *dev_name, void *data, struct vfsmount *mnt)
{
struct nilfs_super_data sd;
- struct super_block *s, *s2;
- struct the_nilfs *nilfs = NULL;
+ struct super_block *s;
+ struct the_nilfs *nilfs;
int err, need_to_close = 1;
sd.bdev = open_bdev_exclusive(dev_name, flags, fs_type);
@@ -1095,7 +1091,6 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags,
* much more information than normal filesystems to identify mount
* instance. For snapshot mounts, not only a mount type (ro-mount
* or rw-mount) but also a checkpoint number is required.
- * The results are passed in sget() using nilfs_super_data.
*/
sd.cno = 0;
sd.flags = flags;
@@ -1104,64 +1099,59 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags,
goto failed;
}
- /*
- * once the super is inserted into the list by sget, s_umount
- * will protect the lockfs code from trying to start a snapshot
- * while we are mounting
- */
- down(&sd.bdev->bd_mount_sem);
- if (!sd.cno &&
- (err = test_exclusive_mount(fs_type, sd.bdev, flags ^ MS_RDONLY))) {
- err = (err < 0) ? : -EBUSY;
- goto failed_unlock;
+ nilfs = find_or_create_nilfs(sd.bdev);
+ if (!nilfs) {
+ err = -ENOMEM;
+ goto failed;
}
- /*
- * Phase-1: search any existent instance and get the_nilfs
- */
- s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, &sd);
- if (IS_ERR(s))
- goto error_s;
-
- if (!s->s_root) {
- err = -ENOMEM;
- nilfs = alloc_nilfs(sd.bdev);
- if (!nilfs)
- goto cancel_new;
- } else {
- struct nilfs_sb_info *sbi = NILFS_SB(s);
+ mutex_lock(&nilfs->ns_mount_mutex);
+ if (!sd.cno) {
/*
- * s_umount protects super_block from unmount process;
- * It covers pointers of nilfs_sb_info and the_nilfs.
+ * Check if an exclusive mount exists or not.
+ * Snapshot mounts coexist with a current mount
+ * (i.e. rw-mount or ro-mount), whereas rw-mount and
+ * ro-mount are mutually exclusive.
*/
- nilfs = sbi->s_nilfs;
- get_nilfs(nilfs);
- up_write(&s->s_umount);
+ down_read(&nilfs->ns_super_sem);
+ if (nilfs->ns_current &&
+ ((nilfs->ns_current->s_super->s_flags ^ flags)
+ & MS_RDONLY)) {
+ up_read(&nilfs->ns_super_sem);
+ err = -EBUSY;
+ goto failed_unlock;
+ }
+ up_read(&nilfs->ns_super_sem);
+ }
- /*
- * Phase-2: search specified snapshot or R/W mode super_block
- */
- if (!sd.cno)
- /* trying to get the latest checkpoint. */
- sd.cno = nilfs_last_cno(nilfs);
+ /*
+ * Find existing nilfs_sb_info struct
+ */
+ sd.sbi = nilfs_find_sbinfo(nilfs, !(flags & MS_RDONLY), sd.cno);
- s2 = sget(fs_type, nilfs_test_bdev_super2,
- nilfs_set_bdev_super, &sd);
- deactivate_super(s);
- /*
- * Although deactivate_super() invokes close_bdev_exclusive() at
- * kill_block_super(). Here, s is an existent mount; we need
- * one more close_bdev_exclusive() call.
- */
- s = s2;
- if (IS_ERR(s))
- goto error_s;
+ if (!sd.cno)
+ /* trying to get the latest checkpoint. */
+ sd.cno = nilfs_last_cno(nilfs);
+
+ /*
+ * Get super block instance holding the nilfs_sb_info struct.
+ * A new instance is allocated if no existing mount is present or
+ * existing instance has been unmounted.
+ */
+ s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, &sd);
+ if (sd.sbi)
+ nilfs_put_sbinfo(sd.sbi);
+
+ if (IS_ERR(s)) {
+ err = PTR_ERR(s);
+ goto failed_unlock;
}
if (!s->s_root) {
char b[BDEVNAME_SIZE];
+ /* New superblock instance created */
s->s_flags = flags;
strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id));
sb_set_blocksize(s, block_size(sd.bdev));
@@ -1172,26 +1162,18 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags,
s->s_flags |= MS_ACTIVE;
need_to_close = 0;
- } else if (!(s->s_flags & MS_RDONLY)) {
- err = -EBUSY;
}
- up(&sd.bdev->bd_mount_sem);
+ mutex_unlock(&nilfs->ns_mount_mutex);
put_nilfs(nilfs);
if (need_to_close)
close_bdev_exclusive(sd.bdev, flags);
simple_set_mnt(mnt, s);
return 0;
- error_s:
- up(&sd.bdev->bd_mount_sem);
- if (nilfs)
- put_nilfs(nilfs);
- close_bdev_exclusive(sd.bdev, flags);
- return PTR_ERR(s);
-
failed_unlock:
- up(&sd.bdev->bd_mount_sem);
+ mutex_unlock(&nilfs->ns_mount_mutex);
+ put_nilfs(nilfs);
failed:
close_bdev_exclusive(sd.bdev, flags);
@@ -1199,70 +1181,18 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags,
cancel_new:
/* Abandoning the newly allocated superblock */
- up(&sd.bdev->bd_mount_sem);
- if (nilfs)
- put_nilfs(nilfs);
+ mutex_unlock(&nilfs->ns_mount_mutex);
+ put_nilfs(nilfs);
up_write(&s->s_umount);
deactivate_super(s);
/*
* deactivate_super() invokes close_bdev_exclusive().
* We must finish all post-cleaning before this call;
- * put_nilfs() and unlocking bd_mount_sem need the block device.
+ * put_nilfs() needs the block device.
*/
return err;
}
-static int nilfs_test_bdev_super3(struct super_block *s, void *data)
-{
- struct nilfs_super_data *sd = data;
- int ret;
-
- if (s->s_bdev != sd->bdev)
- return 0;
- if (down_read_trylock(&s->s_umount)) {
- ret = (s->s_flags & MS_RDONLY) && s->s_root &&
- nilfs_test_opt(NILFS_SB(s), SNAPSHOT);
- up_read(&s->s_umount);
- if (ret)
- return 0; /* ignore snapshot mounts */
- }
- return !((sd->flags ^ s->s_flags) & MS_RDONLY);
-}
-
-static int __false_bdev_super(struct super_block *s, void *data)
-{
-#if 0 /* XXX: workaround for lock debug. This is not good idea */
- up_write(&s->s_umount);
-#endif
- return -EFAULT;
-}
-
-/**
- * test_exclusive_mount - check whether an exclusive RW/RO mount exists or not.
- * fs_type: filesystem type
- * bdev: block device
- * flag: 0 (check rw-mount) or MS_RDONLY (check ro-mount)
- * res: pointer to an integer to store result
- *
- * This function must be called within a section protected by bd_mount_mutex.
- */
-static int test_exclusive_mount(struct file_system_type *fs_type,
- struct block_device *bdev, int flags)
-{
- struct super_block *s;
- struct nilfs_super_data sd = { .flags = flags, .bdev = bdev };
-
- s = sget(fs_type, nilfs_test_bdev_super3, __false_bdev_super, &sd);
- if (IS_ERR(s)) {
- if (PTR_ERR(s) != -EFAULT)
- return PTR_ERR(s);
- return 0; /* Not found */
- }
- up_write(&s->s_umount);
- deactivate_super(s);
- return 1; /* Found */
-}
-
struct file_system_type nilfs_fs_type = {
.owner = THIS_MODULE,
.name = "nilfs2",
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