From 323ee8fc544d407eb053471b9607f95f987f5f12 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 12 May 2016 20:02:09 -0400 Subject: [PATCH] hfsplus: switch to ->iterate_shared() We need to protect the list of hfsplus_readdir_data against parallel insertions (in readdir) and removals (in release). Add a spinlock for that. Note that it has nothing to do with protection of hfsplus_readdir_data->key - we have an exclusion between hfsplus_readdir() and hfsplus_delete_cat() on directory lock and between several hfsplus_readdir() for the same struct file on ->f_pos_lock. The spinlock is strictly for list changes. Signed-off-by: Al Viro --- fs/hfsplus/catalog.c | 3 +++ fs/hfsplus/dir.c | 12 +++++++++--- fs/hfsplus/hfsplus_fs.h | 1 + fs/hfsplus/inode.c | 1 + fs/hfsplus/super.c | 1 + 5 files changed, 15 insertions(+), 3 deletions(-) diff --git a/fs/hfsplus/catalog.c b/fs/hfsplus/catalog.c index 022974ab6e3c..fb707e8f423a 100644 --- a/fs/hfsplus/catalog.c +++ b/fs/hfsplus/catalog.c @@ -374,12 +374,15 @@ int hfsplus_delete_cat(u32 cnid, struct inode *dir, struct qstr *str) hfsplus_free_fork(sb, cnid, &fork, HFSPLUS_TYPE_RSRC); } + /* we only need to take spinlock for exclusion with ->release() */ + spin_lock(&HFSPLUS_I(dir)->open_dir_lock); list_for_each(pos, &HFSPLUS_I(dir)->open_dir_list) { struct hfsplus_readdir_data *rd = list_entry(pos, struct hfsplus_readdir_data, list); if (fd.tree->keycmp(fd.search_key, (void *)&rd->key) < 0) rd->file->f_pos--; } + spin_unlock(&HFSPLUS_I(dir)->open_dir_lock); err = hfs_brec_remove(&fd); if (err) diff --git a/fs/hfsplus/dir.c b/fs/hfsplus/dir.c index a4e867e08947..42e128661dc1 100644 --- a/fs/hfsplus/dir.c +++ b/fs/hfsplus/dir.c @@ -271,8 +271,14 @@ next: } file->private_data = rd; rd->file = file; + spin_lock(&HFSPLUS_I(inode)->open_dir_lock); list_add(&rd->list, &HFSPLUS_I(inode)->open_dir_list); + spin_unlock(&HFSPLUS_I(inode)->open_dir_lock); } + /* + * Can be done after the list insertion; exclusion with + * hfsplus_delete_cat() is provided by directory lock. + */ memcpy(&rd->key, fd.key, sizeof(struct hfsplus_cat_key)); out: kfree(strbuf); @@ -284,9 +290,9 @@ static int hfsplus_dir_release(struct inode *inode, struct file *file) { struct hfsplus_readdir_data *rd = file->private_data; if (rd) { - inode_lock(inode); + spin_lock(&HFSPLUS_I(inode)->open_dir_lock); list_del(&rd->list); - inode_unlock(inode); + spin_unlock(&HFSPLUS_I(inode)->open_dir_lock); kfree(rd); } return 0; @@ -569,7 +575,7 @@ const struct inode_operations hfsplus_dir_inode_operations = { const struct file_operations hfsplus_dir_operations = { .fsync = hfsplus_file_fsync, .read = generic_read_dir, - .iterate = hfsplus_readdir, + .iterate_shared = hfsplus_readdir, .unlocked_ioctl = hfsplus_ioctl, .llseek = generic_file_llseek, .release = hfsplus_dir_release, diff --git a/fs/hfsplus/hfsplus_fs.h b/fs/hfsplus/hfsplus_fs.h index f91a1faf819e..fdc3446d934a 100644 --- a/fs/hfsplus/hfsplus_fs.h +++ b/fs/hfsplus/hfsplus_fs.h @@ -244,6 +244,7 @@ struct hfsplus_inode_info { u8 userflags; /* BSD user file flags */ u32 subfolders; /* Subfolder count (HFSX only) */ struct list_head open_dir_list; + spinlock_t open_dir_lock; loff_t phys_size; struct inode vfs_inode; diff --git a/fs/hfsplus/inode.c b/fs/hfsplus/inode.c index b28f39865c3a..037f738c5871 100644 --- a/fs/hfsplus/inode.c +++ b/fs/hfsplus/inode.c @@ -374,6 +374,7 @@ struct inode *hfsplus_new_inode(struct super_block *sb, umode_t mode) hip = HFSPLUS_I(inode); INIT_LIST_HEAD(&hip->open_dir_list); + spin_lock_init(&hip->open_dir_lock); mutex_init(&hip->extents_lock); atomic_set(&hip->opencnt, 0); hip->extent_state = 0; diff --git a/fs/hfsplus/super.c b/fs/hfsplus/super.c index c35911362ff9..755bf30ba1ce 100644 --- a/fs/hfsplus/super.c +++ b/fs/hfsplus/super.c @@ -67,6 +67,7 @@ struct inode *hfsplus_iget(struct super_block *sb, unsigned long ino) return inode; INIT_LIST_HEAD(&HFSPLUS_I(inode)->open_dir_list); + spin_lock_init(&HFSPLUS_I(inode)->open_dir_lock); mutex_init(&HFSPLUS_I(inode)->extents_lock); HFSPLUS_I(inode)->flags = 0; HFSPLUS_I(inode)->extent_state = 0; -- 2.20.1