hfsplus: add per-superblock lock for volume header updates

Lock updates to the mutal fields in the volume header, and document the
locing in the hfsplus_sb_info structure.

Signed-off-by: Christoph Hellwig <hch@tuxera.com>

diff --git a/fs/hfsplus/dir.c b/fs/hfsplus/dir.c
index f8ae468..1c81eed 100644 (file)
--- a/fs/hfsplus/dir.c
+++ b/fs/hfsplus/dir.c
@@ -251,6 +251,7 @@ static int hfsplus_link(struct dentry *src_dentry, struct inode *dst_dir,
        if (HFSPLUS_IS_RSRC(inode))
                return -EPERM;
 
+       mutex_lock(&sbi->vh_mutex);
        if (inode->i_ino == (u32)(unsigned long)src_dentry->d_fsdata) {
                for (;;) {
                        get_random_bytes(&id, sizeof(cnid));
@@ -263,7 +264,7 @@ static int hfsplus_link(struct dentry *src_dentry, struct inode *dst_dir,
                        if (!res)
                                break;
                        if (res != -EEXIST)
-                               return res;
+                               goto out;
                }
                HFSPLUS_I(inode)->dev = id;
                cnid = sbi->next_cnid++;
@@ -271,13 +272,13 @@ static int hfsplus_link(struct dentry *src_dentry, struct inode *dst_dir,
                res = hfsplus_create_cat(cnid, src_dir, &src_dentry->d_name, inode);
                if (res)
                        /* panic? */
-                       return res;
+                       goto out;
                sbi->file_count++;
        }
        cnid = sbi->next_cnid++;
        res = hfsplus_create_cat(cnid, dst_dir, &dst_dentry->d_name, inode);
        if (res)
-               return res;
+               goto out;
 
        inc_nlink(inode);
        hfsplus_instantiate(dst_dentry, inode, cnid);
@@ -286,8 +287,9 @@ static int hfsplus_link(struct dentry *src_dentry, struct inode *dst_dir,
        mark_inode_dirty(inode);
        sbi->file_count++;
        dst_dir->i_sb->s_dirt = 1;
-
-       return 0;
+out:
+       mutex_unlock(&sbi->vh_mutex);
+       return res;
 }
 
 static int hfsplus_unlink(struct inode *dir, struct dentry *dentry)
@@ -302,6 +304,7 @@ static int hfsplus_unlink(struct inode *dir, struct dentry *dentry)
        if (HFSPLUS_IS_RSRC(inode))
                return -EPERM;
 
+       mutex_lock(&sbi->vh_mutex);
        cnid = (u32)(unsigned long)dentry->d_fsdata;
        if (inode->i_ino == cnid &&
            atomic_read(&HFSPLUS_I(inode)->opencnt)) {
@@ -312,11 +315,11 @@ static int hfsplus_unlink(struct inode *dir, struct dentry *dentry)
                                         sbi->hidden_dir, &str);
                if (!res)
                        inode->i_flags |= S_DEAD;
-               return res;
+               goto out;
        }
        res = hfsplus_delete_cat(cnid, dir, &dentry->d_name);
        if (res)
-               return res;
+               goto out;
 
        if (inode->i_nlink > 0)
                drop_nlink(inode);
@@ -339,37 +342,44 @@ static int hfsplus_unlink(struct inode *dir, struct dentry *dentry)
                sbi->file_count--;
        inode->i_ctime = CURRENT_TIME_SEC;
        mark_inode_dirty(inode);
-
+out:
+       mutex_unlock(&sbi->vh_mutex);
        return res;
 }
 
 static int hfsplus_rmdir(struct inode *dir, struct dentry *dentry)
 {
-       struct inode *inode;
+       struct hfsplus_sb_info *sbi = HFSPLUS_SB(dir->i_sb);
+       struct inode *inode = dentry->d_inode;
        int res;
 
-       inode = dentry->d_inode;
        if (inode->i_size != 2)
                return -ENOTEMPTY;
+
+       mutex_lock(&sbi->vh_mutex);
        res = hfsplus_delete_cat(inode->i_ino, dir, &dentry->d_name);
        if (res)
-               return res;
+               goto out;
        clear_nlink(inode);
        inode->i_ctime = CURRENT_TIME_SEC;
        hfsplus_delete_inode(inode);
        mark_inode_dirty(inode);
-       return 0;
+out:
+       mutex_unlock(&sbi->vh_mutex);
+       return res;
 }
 
 static int hfsplus_symlink(struct inode *dir, struct dentry *dentry,
                           const char *symname)
 {
+       struct hfsplus_sb_info *sbi = HFSPLUS_SB(dir->i_sb);
        struct inode *inode;
-       int res;
+       int res = -ENOSPC;
 
+       mutex_lock(&sbi->vh_mutex);
        inode = hfsplus_new_inode(dir->i_sb, S_IFLNK | S_IRWXUGO);
        if (!inode)
-               return -ENOSPC;
+               goto out;
 
        res = page_symlink(inode, symname, strlen(symname) + 1);
        if (res)
@@ -381,31 +391,35 @@ static int hfsplus_symlink(struct inode *dir, struct dentry *dentry,
 
        hfsplus_instantiate(dentry, inode, inode->i_ino);
        mark_inode_dirty(inode);
-       return 0;
+       goto out;
 
 out_err:
        inode->i_nlink = 0;
        hfsplus_delete_inode(inode);
        iput(inode);
+out:
+       mutex_unlock(&sbi->vh_mutex);
        return res;
 }
 
 static int hfsplus_mknod(struct inode *dir, struct dentry *dentry,
                         int mode, dev_t rdev)
 {
+       struct hfsplus_sb_info *sbi = HFSPLUS_SB(dir->i_sb);
        struct inode *inode;
-       int res;
+       int res = -ENOSPC;
 
+       mutex_lock(&sbi->vh_mutex);
        inode = hfsplus_new_inode(dir->i_sb, mode);
        if (!inode)
-               return -ENOSPC;
+               goto out;
 
        res = hfsplus_create_cat(inode->i_ino, dir, &dentry->d_name, inode);
        if (res) {
                inode->i_nlink = 0;
                hfsplus_delete_inode(inode);
                iput(inode);
-               return res;
+               goto out;
        }
 
        if (S_ISBLK(mode) || S_ISCHR(mode) || S_ISFIFO(mode) || S_ISSOCK(mode))
@@ -413,7 +427,9 @@ static int hfsplus_mknod(struct inode *dir, struct dentry *dentry,
 
        hfsplus_instantiate(dentry, inode, inode->i_ino);
        mark_inode_dirty(inode);
-       return 0;
+out:
+       mutex_unlock(&sbi->vh_mutex);
+       return res;
 }
 
 static int hfsplus_create(struct inode *dir, struct dentry *dentry, int mode,

diff --git a/fs/hfsplus/hfsplus_fs.h b/fs/hfsplus/hfsplus_fs.h
index 0cd9ba0..08865ed 100644 (file)
--- a/fs/hfsplus/hfsplus_fs.h
+++ b/fs/hfsplus/hfsplus_fs.h
@@ -116,23 +116,26 @@ struct hfsplus_sb_info {
        struct inode *hidden_dir;
        struct nls_table *nls;
 
-       /* synchronize block allocations */
-       struct mutex alloc_mutex;
-
        /* Runtime variables */
        u32 blockoffset;
        u32 sect_count;
        int fs_shift;
 
-       /* Stuff in host order from Vol Header */
+       /* immutable data from the volume header */
        u32 alloc_blksz;
        int alloc_blksz_shift;
        u32 total_blocks;
+       u32 data_clump_blocks, rsrc_clump_blocks;
+
+       /* mutable data from the volume header, protected by alloc_mutex */
        u32 free_blocks;
+       struct mutex alloc_mutex;
+
+       /* mutable data from the volume header, protected by vh_mutex */
        u32 next_cnid;
        u32 file_count;
        u32 folder_count;
-       u32 data_clump_blocks, rsrc_clump_blocks;
+       struct mutex vh_mutex;
 
        /* Config options */
        u32 creator;

diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c
index 923f385..b766c17 100644 (file)
--- a/fs/hfsplus/super.c
+++ b/fs/hfsplus/super.c
@@ -160,6 +160,7 @@ int hfsplus_sync_fs(struct super_block *sb, int wait)
 
        dprint(DBG_SUPER, "hfsplus_write_super\n");
 
+       mutex_lock(&sbi->vh_mutex);
        mutex_lock(&sbi->alloc_mutex);
        sb->s_dirt = 0;
 
@@ -194,6 +195,7 @@ int hfsplus_sync_fs(struct super_block *sb, int wait)
                sbi->flags &= ~HFSPLUS_SB_WRITEBACKUP;
        }
        mutex_unlock(&sbi->alloc_mutex);
+       mutex_unlock(&sbi->vh_mutex);
        return 0;
 }
 
@@ -319,6 +321,7 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)
 
        sb->s_fs_info = sbi;
        mutex_init(&sbi->alloc_mutex);
+       mutex_init(&sbi->vh_mutex);
        hfsplus_fill_defaults(sbi);
        if (!hfsplus_parse_options(data, sbi)) {
                printk(KERN_ERR "hfs: unable to parse mount options\n");
@@ -453,9 +456,13 @@ static int hfsplus_fill_super(struct super_block *sb, void *data, int silent)
 
        if (!sbi->hidden_dir) {
                printk(KERN_DEBUG "hfs: create hidden dir...\n");
+
+               mutex_lock(&sbi->vh_mutex);
                sbi->hidden_dir = hfsplus_new_inode(sb, S_IFDIR);
                hfsplus_create_cat(sbi->hidden_dir->i_ino, sb->s_root->d_inode,
                                   &str, sbi->hidden_dir);
+               mutex_unlock(&sbi->vh_mutex);
+
                mark_inode_dirty(sbi->hidden_dir);
        }
 out: