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authorLinus Torvalds <torvalds@linux-foundation.org>2018-08-22 03:19:09 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-22 03:19:09 +0200
commitd9a185f8b49678775ef56ecbdbc7b76970302897 (patch)
tree7ace1b26133e5d796af09e5d71d6531bcb69865c /fs/file_table.c
parentMerge tag 'xfs-4.19-merge-7' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux (diff)
parentovl: Enable metadata only feature (diff)
downloadlinux-d9a185f8b49678775ef56ecbdbc7b76970302897.tar.xz
linux-d9a185f8b49678775ef56ecbdbc7b76970302897.zip
Merge tag 'ovl-update-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs updates from Miklos Szeredi: "This contains two new features: - Stack file operations: this allows removal of several hacks from the VFS, proper interaction of read-only open files with copy-up, possibility to implement fs modifying ioctls properly, and others. - Metadata only copy-up: when file is on lower layer and only metadata is modified (except size) then only copy up the metadata and continue to use the data from the lower file" * tag 'ovl-update-4.19' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (66 commits) ovl: Enable metadata only feature ovl: Do not do metacopy only for ioctl modifying file attr ovl: Do not do metadata only copy-up for truncate operation ovl: add helper to force data copy-up ovl: Check redirect on index as well ovl: Set redirect on upper inode when it is linked ovl: Set redirect on metacopy files upon rename ovl: Do not set dentry type ORIGIN for broken hardlinks ovl: Add an inode flag OVL_CONST_INO ovl: Treat metacopy dentries as type OVL_PATH_MERGE ovl: Check redirects for metacopy files ovl: Move some dir related ovl_lookup_single() code in else block ovl: Do not expose metacopy only dentry from d_real() ovl: Open file with data except for the case of fsync ovl: Add helper ovl_inode_realdata() ovl: Store lower data inode in ovl_inode ovl: Fix ovl_getattr() to get number of blocks from lower ovl: Add helper ovl_dentry_lowerdata() to get lower data dentry ovl: Copy up meta inode data from lowest data inode ovl: Modify ovl_lookup() and friends to lookup metacopy dentry ...
Diffstat (limited to 'fs/file_table.c')
-rw-r--r--fs/file_table.c69
1 files changed, 48 insertions, 21 deletions
diff --git a/fs/file_table.c b/fs/file_table.c
index d6eccd04d703..e49af4caf15d 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -52,7 +52,8 @@ static void file_free_rcu(struct rcu_head *head)
static inline void file_free(struct file *f)
{
security_file_free(f);
- percpu_counter_dec(&nr_files);
+ if (!(f->f_mode & FMODE_NOACCOUNT))
+ percpu_counter_dec(&nr_files);
call_rcu(&f->f_u.fu_rcuhead, file_free_rcu);
}
@@ -91,6 +92,34 @@ int proc_nr_files(struct ctl_table *table, int write,
}
#endif
+static struct file *__alloc_file(int flags, const struct cred *cred)
+{
+ struct file *f;
+ int error;
+
+ f = kmem_cache_zalloc(filp_cachep, GFP_KERNEL);
+ if (unlikely(!f))
+ return ERR_PTR(-ENOMEM);
+
+ f->f_cred = get_cred(cred);
+ error = security_file_alloc(f);
+ if (unlikely(error)) {
+ file_free_rcu(&f->f_u.fu_rcuhead);
+ return ERR_PTR(error);
+ }
+
+ atomic_long_set(&f->f_count, 1);
+ rwlock_init(&f->f_owner.lock);
+ spin_lock_init(&f->f_lock);
+ mutex_init(&f->f_pos_lock);
+ eventpoll_init_file(f);
+ f->f_flags = flags;
+ f->f_mode = OPEN_FMODE(flags);
+ /* f->f_version: 0 */
+
+ return f;
+}
+
/* Find an unused file structure and return a pointer to it.
* Returns an error pointer if some error happend e.g. we over file
* structures limit, run out of memory or operation is not permitted.
@@ -105,7 +134,6 @@ struct file *alloc_empty_file(int flags, const struct cred *cred)
{
static long old_max;
struct file *f;
- int error;
/*
* Privileged users can go above max_files
@@ -119,26 +147,10 @@ struct file *alloc_empty_file(int flags, const struct cred *cred)
goto over;
}
- f = kmem_cache_zalloc(filp_cachep, GFP_KERNEL);
- if (unlikely(!f))
- return ERR_PTR(-ENOMEM);
-
- f->f_cred = get_cred(cred);
- error = security_file_alloc(f);
- if (unlikely(error)) {
- file_free_rcu(&f->f_u.fu_rcuhead);
- return ERR_PTR(error);
- }
+ f = __alloc_file(flags, cred);
+ if (!IS_ERR(f))
+ percpu_counter_inc(&nr_files);
- atomic_long_set(&f->f_count, 1);
- rwlock_init(&f->f_owner.lock);
- spin_lock_init(&f->f_lock);
- mutex_init(&f->f_pos_lock);
- eventpoll_init_file(f);
- f->f_flags = flags;
- f->f_mode = OPEN_FMODE(flags);
- /* f->f_version: 0 */
- percpu_counter_inc(&nr_files);
return f;
over:
@@ -150,6 +162,21 @@ over:
return ERR_PTR(-ENFILE);
}
+/*
+ * Variant of alloc_empty_file() that doesn't check and modify nr_files.
+ *
+ * Should not be used unless there's a very good reason to do so.
+ */
+struct file *alloc_empty_file_noaccount(int flags, const struct cred *cred)
+{
+ struct file *f = __alloc_file(flags, cred);
+
+ if (!IS_ERR(f))
+ f->f_mode |= FMODE_NOACCOUNT;
+
+ return f;
+}
+
/**
* alloc_file - allocate and initialize a 'struct file'
*