This stops pre-allocating nilfs object in nilfs_get_sb routine, and
stops managing its life cycle by reference counting.
nilfs_find_or_create_nilfs() function, nilfs->ns_mount_mutex,
nilfs_objects list, and the reference counter will be removed through
the simplification.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxxxxxx>
---
fs/nilfs2/ioctl.c | 4 +-
fs/nilfs2/super.c | 67 ++++++++++++++-----------------------------
fs/nilfs2/the_nilfs.c | 75 +++---------------------------------------------
fs/nilfs2/the_nilfs.h | 16 +---------
4 files changed, 31 insertions(+), 131 deletions(-)
diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
index f0a99bd..85274f0 100644
--- a/fs/nilfs2/ioctl.c
+++ b/fs/nilfs2/ioctl.c
@@ -118,7 +118,7 @@ static int nilfs_ioctl_change_cpmode(struct inode *inode, struct file *filp,
if (copy_from_user(&cpmode, argp, sizeof(cpmode)))
goto out;
- mutex_lock(&nilfs->ns_mount_mutex);
+ down_read(&inode->i_sb->s_umount);
nilfs_transaction_begin(inode->i_sb, &ti, 0);
ret = nilfs_cpfile_change_cpmode(
@@ -128,7 +128,7 @@ static int nilfs_ioctl_change_cpmode(struct inode *inode, struct file *filp,
else
nilfs_transaction_commit(inode->i_sb); /* never fails */
- mutex_unlock(&nilfs->ns_mount_mutex);
+ up_read(&inode->i_sb->s_umount);
out:
mnt_drop_write(filp->f_path.mnt);
return ret;
diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index bd2eb42..411ee2e 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -359,7 +359,7 @@ static void nilfs_put_super(struct super_block *sb)
up_write(&nilfs->ns_sem);
}
- put_nilfs(sbi->s_nilfs);
+ destroy_nilfs(nilfs);
sbi->s_super = NULL;
sb->s_fs_info = NULL;
kfree(sbi);
@@ -841,15 +841,14 @@ static int nilfs_try_to_shrink_tree(struct dentry *root_dentry)
* @sb: super_block
* @data: mount options
* @silent: silent mode flag
- * @nilfs: the_nilfs struct
*
* This function is called exclusively by nilfs->ns_mount_mutex.
* So, the recovery process is protected from other simultaneous mounts.
*/
static int
-nilfs_fill_super(struct super_block *sb, void *data, int silent,
- struct the_nilfs *nilfs)
+nilfs_fill_super(struct super_block *sb, void *data, int silent)
{
+ struct the_nilfs *nilfs;
struct nilfs_sb_info *sbi;
struct nilfs_root *fsroot;
__u64 cno;
@@ -860,14 +859,18 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent,
return -ENOMEM;
sb->s_fs_info = sbi;
+ sbi->s_super = sb;
- get_nilfs(nilfs);
+ nilfs = alloc_nilfs(sb->s_bdev);
+ if (!nilfs) {
+ err = -ENOMEM;
+ goto failed_sbi;
+ }
sbi->s_nilfs = nilfs;
- sbi->s_super = sb;
err = init_nilfs(nilfs, sbi, (char *)data);
if (err)
- goto failed_sbi;
+ goto failed_nilfs;
spin_lock_init(&sbi->s_inode_lock);
INIT_LIST_HEAD(&sbi->s_dirty_files);
@@ -890,14 +893,14 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent,
err = load_nilfs(nilfs, sbi);
if (err)
- goto failed_sbi;
+ goto failed_nilfs;
cno = nilfs_last_cno(nilfs);
err = nilfs_attach_checkpoint(sbi, cno, true, &fsroot);
if (err) {
printk(KERN_ERR "NILFS: error loading last checkpoint "
"(checkpoint number=%llu).\n", (unsigned long long)cno);
- goto failed_sbi;
+ goto failed_nilfs;
}
if (!(sb->s_flags & MS_RDONLY)) {
@@ -926,8 +929,10 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent,
failed_checkpoint:
nilfs_put_root(fsroot);
+ failed_nilfs:
+ destroy_nilfs(nilfs);
+
failed_sbi:
- put_nilfs(nilfs);
sb->s_fs_info = NULL;
kfree(sbi);
return err;
@@ -1086,7 +1091,6 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags,
struct nilfs_super_data sd;
struct super_block *s;
fmode_t mode = FMODE_READ;
- struct the_nilfs *nilfs;
struct dentry *root_dentry;
int err, s_new = false;
@@ -1104,18 +1108,10 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags,
goto failed;
}
- nilfs = find_or_create_nilfs(sd.bdev);
- if (!nilfs) {
- err = -ENOMEM;
- goto failed;
- }
-
- mutex_lock(&nilfs->ns_mount_mutex);
-
s = sget(fs_type, nilfs_test_bdev_super, nilfs_set_bdev_super, sd.bdev);
if (IS_ERR(s)) {
err = PTR_ERR(s);
- goto failed_unlock;
+ goto failed;
}
if (!s->s_root) {
@@ -1129,10 +1125,9 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags,
strlcpy(s->s_id, bdevname(sd.bdev, b), sizeof(s->s_id));
sb_set_blocksize(s, block_size(sd.bdev));
- err = nilfs_fill_super(s, data, flags & MS_SILENT ? 1 : 0,
- nilfs);
+ err = nilfs_fill_super(s, data, flags & MS_SILENT ? 1 : 0);
if (err)
- goto cancel_new;
+ goto failed_super;
s->s_flags |= MS_ACTIVE;
} else if (!sd.cno) {
@@ -1162,17 +1157,12 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags,
if (sd.cno) {
err = nilfs_attach_snapshot(s, sd.cno, &root_dentry);
- if (err) {
- if (s_new)
- goto cancel_new;
+ if (err)
goto failed_super;
- }
} else {
root_dentry = dget(s->s_root);
}
- mutex_unlock(&nilfs->ns_mount_mutex);
- put_nilfs(nilfs);
if (!s_new)
close_bdev_exclusive(sd.bdev, mode);
@@ -1182,24 +1172,11 @@ nilfs_get_sb(struct file_system_type *fs_type, int flags,
failed_super:
deactivate_locked_super(s);
- failed_unlock:
- mutex_unlock(&nilfs->ns_mount_mutex);
- put_nilfs(nilfs);
- failed:
- close_bdev_exclusive(sd.bdev, mode);
- return err;
+ failed:
+ if (!s_new)
+ close_bdev_exclusive(sd.bdev, mode);
- cancel_new:
- /* Abandoning the newly allocated superblock */
- mutex_unlock(&nilfs->ns_mount_mutex);
- put_nilfs(nilfs);
- deactivate_locked_super(s);
- /*
- * This deactivate_locked_super() invokes close_bdev_exclusive().
- * We must finish all post-cleaning before this call;
- * put_nilfs() needs the block device.
- */
return err;
}
diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c
index e8d950d..bc9a3e2 100644
--- a/fs/nilfs2/the_nilfs.c
+++ b/fs/nilfs2/the_nilfs.c
@@ -35,9 +35,6 @@
#include "segbuf.h"
-static LIST_HEAD(nilfs_objects);
-static DEFINE_SPINLOCK(nilfs_lock);
-
static int nilfs_valid_sb(struct nilfs_super_block *sbp);
void nilfs_set_last_segment(struct the_nilfs *nilfs,
@@ -61,16 +58,13 @@ void nilfs_set_last_segment(struct the_nilfs *nilfs,
}
/**
- * alloc_nilfs - allocate the_nilfs structure
+ * alloc_nilfs - allocate a nilfs object
* @bdev: block device to which the_nilfs is related
*
- * alloc_nilfs() allocates memory for the_nilfs and
- * initializes its reference count and locks.
- *
* Return Value: On success, pointer to the_nilfs is returned.
* On error, NULL is returned.
*/
-static struct the_nilfs *alloc_nilfs(struct block_device *bdev)
+struct the_nilfs *alloc_nilfs(struct block_device *bdev)
{
struct the_nilfs *nilfs;
@@ -79,12 +73,9 @@ static struct the_nilfs *alloc_nilfs(struct block_device *bdev)
return NULL;
nilfs->ns_bdev = bdev;
- atomic_set(&nilfs->ns_count, 1);
atomic_set(&nilfs->ns_ndirtyblks, 0);
init_rwsem(&nilfs->ns_sem);
- mutex_init(&nilfs->ns_mount_mutex);
init_rwsem(&nilfs->ns_writer_sem);
- INIT_LIST_HEAD(&nilfs->ns_list);
INIT_LIST_HEAD(&nilfs->ns_gc_inodes);
spin_lock_init(&nilfs->ns_last_segment_lock);
nilfs->ns_cptree = RB_ROOT;
@@ -95,67 +86,11 @@ static struct the_nilfs *alloc_nilfs(struct block_device *bdev)
}
/**
- * find_or_create_nilfs - find or create nilfs object
- * @bdev: block device to which the_nilfs is related
- *
- * find_nilfs() looks up an existent nilfs object created on the
- * device and gets the reference count of the object. If no nilfs object
- * is found on the device, a new nilfs object is allocated.
- *
- * Return Value: On success, pointer to the nilfs object is returned.
- * On error, NULL is returned.
- */
-struct the_nilfs *find_or_create_nilfs(struct block_device *bdev)
-{
- struct the_nilfs *nilfs, *new = NULL;
-
- retry:
- spin_lock(&nilfs_lock);
- list_for_each_entry(nilfs, &nilfs_objects, ns_list) {
- if (nilfs->ns_bdev == bdev) {
- get_nilfs(nilfs);
- spin_unlock(&nilfs_lock);
- if (new)
- put_nilfs(new);
- return nilfs; /* existing object */
- }
- }
- if (new) {
- list_add_tail(&new->ns_list, &nilfs_objects);
- spin_unlock(&nilfs_lock);
- return new; /* new object */
- }
- spin_unlock(&nilfs_lock);
-
- new = alloc_nilfs(bdev);
- if (new)
- goto retry;
- return NULL; /* insufficient memory */
-}
-
-/**
- * put_nilfs - release a reference to the_nilfs
- * @nilfs: the_nilfs structure to be released
- *
- * put_nilfs() decrements a reference counter of the_nilfs.
- * If the reference count reaches zero, the_nilfs is freed.
+ * destroy_nilfs - destroy nilfs object
+ * @nilfs: nilfs object to be released
*/
-void put_nilfs(struct the_nilfs *nilfs)
+void destroy_nilfs(struct the_nilfs *nilfs)
{
- spin_lock(&nilfs_lock);
- if (!atomic_dec_and_test(&nilfs->ns_count)) {
- spin_unlock(&nilfs_lock);
- return;
- }
- list_del_init(&nilfs->ns_list);
- spin_unlock(&nilfs_lock);
-
- /*
- * Increment of ns_count never occurs below because the caller
- * of get_nilfs() holds at least one reference to the_nilfs.
- * Thus its exclusion control is not required here.
- */
-
might_sleep();
if (nilfs_loaded(nilfs)) {
nilfs_mdt_destroy(nilfs->ns_sufile);
diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h
index 7b43693..1908dc7 100644
--- a/fs/nilfs2/the_nilfs.h
+++ b/fs/nilfs2/the_nilfs.h
@@ -46,13 +46,10 @@ enum {
/**
* struct the_nilfs - struct to supervise multiple nilfs mount points
* @ns_flags: flags
- * @ns_count: reference count
- * @ns_list: list head for nilfs_list
* @ns_bdev: block device
* @ns_bdi: backing dev info
* @ns_writer: back pointer to writable nilfs_sb_info
* @ns_sem: semaphore for shared states
- * @ns_mount_mutex: mutex protecting mount process of nilfs
* @ns_writer_sem: semaphore protecting ns_writer attach/detach
* @ns_sbh: buffer heads of on-disk super blocks
* @ns_sbp: pointers to super block data
@@ -94,14 +91,11 @@ enum {
*/
struct the_nilfs {
unsigned long ns_flags;
- atomic_t ns_count;
- struct list_head ns_list;
struct block_device *ns_bdev;
struct backing_dev_info *ns_bdi;
struct nilfs_sb_info *ns_writer;
struct rw_semaphore ns_sem;
- struct mutex ns_mount_mutex;
struct rw_semaphore ns_writer_sem;
/*
@@ -239,8 +233,8 @@ static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs)
}
void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64);
-struct the_nilfs *find_or_create_nilfs(struct block_device *);
-void put_nilfs(struct the_nilfs *);
+struct the_nilfs *alloc_nilfs(struct block_device *bdev);
+void destroy_nilfs(struct the_nilfs *nilfs);
int init_nilfs(struct the_nilfs *, struct nilfs_sb_info *, char *);
int load_nilfs(struct the_nilfs *, struct nilfs_sb_info *);
int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t);
@@ -256,12 +250,6 @@ void nilfs_fall_back_super_block(struct the_nilfs *);
void nilfs_swap_super_block(struct the_nilfs *);
-static inline void get_nilfs(struct the_nilfs *nilfs)
-{
- /* Caller must have at least one reference of the_nilfs. */
- atomic_inc(&nilfs->ns_count);
-}
-
static inline void nilfs_get_root(struct nilfs_root *root)
{
atomic_inc(&root->count);
--
1.6.6.2
--
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