From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755766Ab2HASer (ORCPT ); Wed, 1 Aug 2012 14:34:47 -0400 Received: from mail-ee0-f74.google.com ([74.125.83.74]:53898 "EHLO mail-ee0-f74.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754961Ab2HASep (ORCPT ); Wed, 1 Aug 2012 14:34:45 -0400 From: anatol.pomozov@gmail.com To: linux-kernel@vger.kernel.org Cc: viro@ZenIV.linux.org.uk, tytso@mit.edu, Anatol Pomazau , Anatol Pomozov Subject: [PATCH] fs: Preserve error code in get_empty_filp() Date: Wed, 1 Aug 2012 11:34:29 -0700 Message-Id: <1343846069-2698-1-git-send-email-anatol.pomozov@gmail.com> X-Mailer: git-send-email 1.7.11.3 In-Reply-To: <1343845147-21394-1-git-send-email-anatol.pomozov@gmail.com> References: <1343845147-21394-1-git-send-email-anatol.pomozov@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Anatol Pomazau Allocating a file structure in function get_empty_filp() might fail because of several reasons: - not enough memory for file structures - operation is not allowed - user is over its limit Currently the function returns NULL in all cases and we loose the exact reason of the error. All callers of get_empty_filp() assume that the function can fail with ENFILE only. Return error through pointer. Change all callers to preserve this error code. Signed-off-by: Anatol Pomozov Reviewed-by: "Theodore Ts'o" --- arch/ia64/kernel/perfmon.c | 4 ++-- fs/anon_inodes.c | 5 +++-- fs/file_table.c | 22 ++++++++++++++-------- fs/hugetlbfs/inode.c | 5 +++-- fs/namei.c | 4 ++-- fs/open.c | 5 ++--- fs/pipe.c | 9 +++++---- ipc/shm.c | 4 +++- mm/shmem.c | 5 +++-- net/socket.c | 4 ++-- 10 files changed, 39 insertions(+), 28 deletions(-) diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c index 3fa4bc5..da2dcce 100644 --- a/arch/ia64/kernel/perfmon.c +++ b/arch/ia64/kernel/perfmon.c @@ -2221,9 +2221,9 @@ pfm_alloc_file(pfm_context_t *ctx) d_add(path.dentry, inode); file = alloc_file(&path, FMODE_READ, &pfm_file_ops); - if (!file) { + if (IS_ERR(file)) { path_put(&path); - return ERR_PTR(-ENFILE); + return file; } file->f_flags = O_RDONLY; diff --git a/fs/anon_inodes.c b/fs/anon_inodes.c index 28d39fb..73536e3 100644 --- a/fs/anon_inodes.c +++ b/fs/anon_inodes.c @@ -160,10 +160,11 @@ struct file *anon_inode_getfile(const char *name, d_instantiate(path.dentry, anon_inode_inode); - error = -ENFILE; file = alloc_file(&path, OPEN_FMODE(flags), fops); - if (!file) + if (IS_ERR(file)) { + error = PTR_ERR(file); goto err_dput; + } file->f_mapping = anon_inode_inode->i_mapping; file->f_pos = 0; diff --git a/fs/file_table.c b/fs/file_table.c index b3fc4d6..88e8c64 100644 --- a/fs/file_table.c +++ b/fs/file_table.c @@ -94,8 +94,8 @@ int proc_nr_files(ctl_table *table, int write, #endif /* Find an unused file structure and return a pointer to it. - * Returns NULL, if there are no more free file structures or - * we run out of memory. + * Returns error pointer if some error happend e.g. we over file + * structures limit, run out of memory or operation is not permitted. * * Be very careful using this. You are responsible for * getting write access to any mount that you might assign @@ -108,6 +108,7 @@ struct file *get_empty_filp(void) const struct cred *cred = current_cred(); static long old_max; struct file * f; + int error; /* * Privileged users can go above max_files @@ -117,17 +118,22 @@ struct file *get_empty_filp(void) * percpu_counters are inaccurate. Do an expensive check before * we go and fail. */ - if (percpu_counter_sum_positive(&nr_files) >= files_stat.max_files) + if (percpu_counter_sum_positive(&nr_files) >= files_stat.max_files) { + error = -ENFILE; goto over; + } } f = kmem_cache_zalloc(filp_cachep, GFP_KERNEL); - if (f == NULL) + if (f == NULL) { + error = -ENOMEM; goto fail; + } percpu_counter_inc(&nr_files); f->f_cred = get_cred(cred); - if (security_file_alloc(f)) + error = security_file_alloc(f); + if (error) goto fail_sec; INIT_LIST_HEAD(&f->f_u.fu_list); @@ -149,7 +155,7 @@ over: fail_sec: file_free(f); fail: - return NULL; + return ERR_PTR(error); } /** @@ -173,8 +179,8 @@ struct file *alloc_file(struct path *path, fmode_t mode, struct file *file; file = get_empty_filp(); - if (!file) - return NULL; + if (IS_ERR(file)) + return file; file->f_path = *path; file->f_mapping = path->dentry->d_inode->i_mapping; diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c index 8349a89..5ec849b 100644 --- a/fs/hugetlbfs/inode.c +++ b/fs/hugetlbfs/inode.c @@ -984,11 +984,12 @@ struct file *hugetlb_file_setup(const char *name, unsigned long addr, inode->i_size = size; clear_nlink(inode); - error = -ENFILE; file = alloc_file(&path, FMODE_WRITE | FMODE_READ, &hugetlbfs_file_operations); - if (!file) + if (IS_ERR(file)) { + error = PTR_ERR(file); goto out_dentry; /* inode is already attached */ + } return file; diff --git a/fs/namei.c b/fs/namei.c index 2ccc35c..b77bdca 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2753,8 +2753,8 @@ static struct file *path_openat(int dfd, const char *pathname, int error; file = get_empty_filp(); - if (!file) - return ERR_PTR(-ENFILE); + if (IS_ERR(file)) + return file; file->f_flags = op->open_flag; diff --git a/fs/open.c b/fs/open.c index 1e914b3..195bdab 100644 --- a/fs/open.c +++ b/fs/open.c @@ -777,10 +777,9 @@ struct file *dentry_open(const struct path *path, int flags, /* We must always pass in a valid mount pointer. */ BUG_ON(!path->mnt); - error = -ENFILE; f = get_empty_filp(); - if (f == NULL) - return ERR_PTR(error); + if (IS_ERR(f)) + return f; f->f_flags = flags; f->f_path = *path; diff --git a/fs/pipe.c b/fs/pipe.c index 95cbd6b..429f2db 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -1037,10 +1037,11 @@ struct file *create_write_pipe(int flags) d_instantiate(path.dentry, inode); - err = -ENFILE; f = alloc_file(&path, FMODE_WRITE, &write_pipefifo_fops); - if (!f) + if (IS_ERR(f)) { + err = PTR_ERR(f); goto err_dentry; + } f->f_mapping = inode->i_mapping; f->f_flags = O_WRONLY | (flags & (O_NONBLOCK | O_DIRECT)); @@ -1072,8 +1073,8 @@ struct file *create_read_pipe(struct file *wrf, int flags) /* Grab pipe from the writer */ struct file *f = alloc_file(&wrf->f_path, FMODE_READ, &read_pipefifo_fops); - if (!f) - return ERR_PTR(-ENFILE); + if (IS_ERR(f)) + return f; path_get(&wrf->f_path); f->f_flags = O_RDONLY | (flags & O_NONBLOCK); diff --git a/ipc/shm.c b/ipc/shm.c index 00faa05..c8eee21 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -1039,8 +1039,10 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr, is_file_hugepages(shp->shm_file) ? &shm_file_operations_huge : &shm_file_operations); - if (!file) + if (IS_ERR(file)) { + err = PTR_ERR(file); goto out_free; + } file->private_data = sfd; file->f_mapping = shp->shm_file->f_mapping; diff --git a/mm/shmem.c b/mm/shmem.c index d4e184e..cd814ee 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2948,11 +2948,12 @@ struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags goto put_dentry; #endif - error = -ENFILE; file = alloc_file(&path, FMODE_WRITE | FMODE_READ, &shmem_file_operations); - if (!file) + if (IS_ERR(file)) { + error = PTR_ERR(file); goto put_dentry; + } return file; diff --git a/net/socket.c b/net/socket.c index dfe5b66..e80eb83 100644 --- a/net/socket.c +++ b/net/socket.c @@ -369,12 +369,12 @@ static int sock_alloc_file(struct socket *sock, struct file **f, int flags) file = alloc_file(&path, FMODE_READ | FMODE_WRITE, &socket_file_ops); - if (unlikely(!file)) { + if (unlikely(IS_ERR(file))) { /* drop dentry, keep inode */ ihold(path.dentry->d_inode); path_put(&path); put_unused_fd(fd); - return -ENFILE; + return PTR_ERR(file); } sock->file = file; -- 1.7.11.3