From 5955102c9984fa081b2d570cfac75c97eecf8f3b Mon Sep 17 00:00:00 2001 From: Al Viro Date: Fri, 22 Jan 2016 15:40:57 -0500 Subject: wrappers for ->i_mutex access parallel to mutex_{lock,unlock,trylock,is_locked,lock_nested}, inode_foo(inode) being mutex_foo(&inode->i_mutex). Please, use those for access to ->i_mutex; over the coming cycle ->i_mutex will become rwsem, with ->lookup() done with it held only shared. Signed-off-by: Al Viro --- include/linux/fs.h | 29 +++++++++++++++++++++++++++-- 1 file changed, 27 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/fs.h b/include/linux/fs.h index eb73d74ed992..2df6c033c3f5 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -714,6 +714,31 @@ enum inode_i_mutex_lock_class I_MUTEX_PARENT2, }; +static inline void inode_lock(struct inode *inode) +{ + mutex_lock(&inode->i_mutex); +} + +static inline void inode_unlock(struct inode *inode) +{ + mutex_unlock(&inode->i_mutex); +} + +static inline int inode_trylock(struct inode *inode) +{ + return mutex_trylock(&inode->i_mutex); +} + +static inline int inode_is_locked(struct inode *inode) +{ + return mutex_is_locked(&inode->i_mutex); +} + +static inline void inode_lock_nested(struct inode *inode, unsigned subclass) +{ + mutex_lock_nested(&inode->i_mutex, subclass); +} + void lock_two_nondirectories(struct inode *, struct inode*); void unlock_two_nondirectories(struct inode *, struct inode*); @@ -3047,8 +3072,8 @@ static inline bool dir_emit_dots(struct file *file, struct dir_context *ctx) } static inline bool dir_relax(struct inode *inode) { - mutex_unlock(&inode->i_mutex); - mutex_lock(&inode->i_mutex); + inode_unlock(inode); + inode_lock(inode); return !IS_DEADDIR(inode); } -- cgit v1.2.3-58-ga151 From 3ed47db34f480df7caf44436e3e63e555351ae9a Mon Sep 17 00:00:00 2001 From: Al Viro Date: Fri, 22 Jan 2016 18:08:52 -0500 Subject: make sure that freeing shmem fast symlinks is RCU-delayed Cc: stable@vger.kernel.org # v4.2+ Signed-off-by: Al Viro --- include/linux/shmem_fs.h | 5 +---- mm/shmem.c | 9 ++++----- 2 files changed, 5 insertions(+), 9 deletions(-) (limited to 'include') diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index a43f41cb3c43..4d4780c00d34 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -15,10 +15,7 @@ struct shmem_inode_info { unsigned int seals; /* shmem seals */ unsigned long flags; unsigned long alloced; /* data pages alloced to file */ - union { - unsigned long swapped; /* subtotal assigned to swap */ - char *symlink; /* unswappable short symlink */ - }; + unsigned long swapped; /* subtotal assigned to swap */ struct shared_policy policy; /* NUMA memory alloc policy */ struct list_head swaplist; /* chain of maybes on swap */ struct simple_xattrs xattrs; /* list of xattrs */ diff --git a/mm/shmem.c b/mm/shmem.c index 38c5e72c7008..440e2a7e6c1c 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -701,8 +701,7 @@ static void shmem_evict_inode(struct inode *inode) list_del_init(&info->swaplist); mutex_unlock(&shmem_swaplist_mutex); } - } else - kfree(info->symlink); + } simple_xattrs_free(&info->xattrs); WARN_ON(inode->i_blocks); @@ -2549,13 +2548,12 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s info = SHMEM_I(inode); inode->i_size = len-1; if (len <= SHORT_SYMLINK_LEN) { - info->symlink = kmemdup(symname, len, GFP_KERNEL); - if (!info->symlink) { + inode->i_link = kmemdup(symname, len, GFP_KERNEL); + if (!inode->i_link) { iput(inode); return -ENOMEM; } inode->i_op = &shmem_short_symlink_operations; - inode->i_link = info->symlink; } else { inode_nohighmem(inode); error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); @@ -3132,6 +3130,7 @@ static struct inode *shmem_alloc_inode(struct super_block *sb) static void shmem_destroy_callback(struct rcu_head *head) { struct inode *inode = container_of(head, struct inode, i_rcu); + kfree(inode->i_link); kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); } -- cgit v1.2.3-58-ga151