summaryrefslogtreecommitdiff
path: root/Documentation
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2018-08-13 19:58:36 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-08-13 19:58:36 -0700
commita66b4cd1e7163adb327838a3c81faaf6a9330d5a (patch)
tree2b123a010bb0f1566ff6f34e529f01ddf10ee308 /Documentation
parentb16528466786a540cb00148acb124e0149d62710 (diff)
parent5f336e722cc961be94d264d96b90c92888fffae1 (diff)
Merge branch 'work.open3' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs open-related updates from Al Viro: - "do we need fput() or put_filp()" rules are gone - it's always fput() now. We keep track of that state where it belongs - in ->f_mode. - int *opened mess killed - in finish_open(), in ->atomic_open() instances and in fs/namei.c code around do_last()/lookup_open()/atomic_open(). - alloc_file() wrappers with saner calling conventions are introduced (alloc_file_clone() and alloc_file_pseudo()); callers converted, with much simplification. - while we are at it, saner calling conventions for path_init() and link_path_walk(), simplifying things inside fs/namei.c (both on open-related paths and elsewhere). * 'work.open3' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (40 commits) few more cleanups of link_path_walk() callers allow link_path_walk() to take ERR_PTR() make path_init() unconditionally paired with terminate_walk() document alloc_file() changes make alloc_file() static do_shmat(): grab shp->shm_file earlier, switch to alloc_file_clone() new helper: alloc_file_clone() create_pipe_files(): switch the first allocation to alloc_file_pseudo() anon_inode_getfile(): switch to alloc_file_pseudo() hugetlb_file_setup(): switch to alloc_file_pseudo() ocxlflash_getfile(): switch to alloc_file_pseudo() cxl_getfile(): switch to alloc_file_pseudo() ... and switch shmem_file_setup() to alloc_file_pseudo() __shmem_file_setup(): reorder allocations new wrapper: alloc_file_pseudo() kill FILE_{CREATED,OPENED} switch atomic_open() and lookup_open() to returning 0 in all success cases document ->atomic_open() changes ->atomic_open(): return 0 in all success cases get rid of 'opened' in path_openat() and the helpers downstream ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/filesystems/Locking2
-rw-r--r--Documentation/filesystems/porting20
-rw-r--r--Documentation/filesystems/vfs.txt18
3 files changed, 31 insertions, 9 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 37bf0a9de75c..7cca82ed2ed1 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -64,7 +64,7 @@ prototypes:
void (*update_time)(struct inode *, struct timespec *, int);
int (*atomic_open)(struct inode *, struct dentry *,
struct file *, unsigned open_flag,
- umode_t create_mode, int *opened);
+ umode_t create_mode);
int (*tmpfile) (struct inode *, struct dentry *, umode_t);
locking rules:
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index 17bb4dc28fae..7b7b845c490a 100644
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -602,3 +602,23 @@ in your dentry operations instead.
dentry separately, and it now has request_mask and query_flags arguments
to specify the fields and sync type requested by statx. Filesystems not
supporting any statx-specific features may ignore the new arguments.
+--
+[mandatory]
+ ->atomic_open() calling conventions have changed. Gone is int *opened,
+ along with FILE_OPENED/FILE_CREATED. In place of those we have
+ FMODE_OPENED/FMODE_CREATED, set in file->f_mode. Additionally, return
+ value for 'called finish_no_open(), open it yourself' case has become
+ 0, not 1. Since finish_no_open() itself is returning 0 now, that part
+ does not need any changes in ->atomic_open() instances.
+--
+[mandatory]
+ alloc_file() has become static now; two wrappers are to be used instead.
+ alloc_file_pseudo(inode, vfsmount, name, flags, ops) is for the cases
+ when dentry needs to be created; that's the majority of old alloc_file()
+ users. Calling conventions: on success a reference to new struct file
+ is returned and callers reference to inode is subsumed by that. On
+ failure, ERR_PTR() is returned and no caller's references are affected,
+ so the caller needs to drop the inode reference it held.
+ alloc_file_clone(file, flags, ops) does not affect any caller's references.
+ On success you get a new struct file sharing the mount/dentry with the
+ original, on failure - ERR_PTR().
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index f608180ad59d..85907d5b9c2c 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -386,7 +386,7 @@ struct inode_operations {
ssize_t (*listxattr) (struct dentry *, char *, size_t);
void (*update_time)(struct inode *, struct timespec *, int);
int (*atomic_open)(struct inode *, struct dentry *, struct file *,
- unsigned open_flag, umode_t create_mode, int *opened);
+ unsigned open_flag, umode_t create_mode);
int (*tmpfile) (struct inode *, struct dentry *, umode_t);
};
@@ -496,13 +496,15 @@ otherwise noted.
atomic_open: called on the last component of an open. Using this optional
method the filesystem can look up, possibly create and open the file in
- one atomic operation. If it cannot perform this (e.g. the file type
- turned out to be wrong) it may signal this by returning 1 instead of
- usual 0 or -ve . This method is only called if the last component is
- negative or needs lookup. Cached positive dentries are still handled by
- f_op->open(). If the file was created, the FILE_CREATED flag should be
- set in "opened". In case of O_EXCL the method must only succeed if the
- file didn't exist and hence FILE_CREATED shall always be set on success.
+ one atomic operation. If it wants to leave actual opening to the
+ caller (e.g. if the file turned out to be a symlink, device, or just
+ something filesystem won't do atomic open for), it may signal this by
+ returning finish_no_open(file, dentry). This method is only called if
+ the last component is negative or needs lookup. Cached positive dentries
+ are still handled by f_op->open(). If the file was created,
+ FMODE_CREATED flag should be set in file->f_mode. In case of O_EXCL
+ the method must only succeed if the file didn't exist and hence FMODE_CREATED
+ shall always be set on success.
tmpfile: called in the end of O_TMPFILE open(). Optional, equivalent to
atomically creating, opening and unlinking a file in given directory.