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author | Linus Torvalds <torvalds@linux-foundation.org> | 2018-06-04 20:14:28 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-06-04 20:14:28 +0300 |
commit | f956d08a56732c61a4d44e8034eeeedfc06fe721 (patch) | |
tree | 2debddf1044e4bfd905ede07480a2867504a4ae3 /Documentation/filesystems/Locking | |
parent | cf626b0da78df6669c6b5f51ddd9a70a0702e579 (diff) | |
parent | eb915375757cd32c5abf7aea4caa76fe7edf8ef4 (diff) | |
download | linux-f956d08a56732c61a4d44e8034eeeedfc06fe721.tar.xz |
Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull misc vfs updates from Al Viro:
"Misc bits and pieces not fitting into anything more specific"
* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
vfs: delete unnecessary assignment in vfs_listxattr
Documentation: filesystems: update filesystem locking documentation
vfs: namei: use path_equal() in follow_dotdot()
fs.h: fix outdated comment about file flags
__inode_security_revalidate() never gets NULL opt_dentry
make xattr_getsecurity() static
vfat: simplify checks in vfat_lookup()
get rid of dead code in d_find_alias()
it's SB_BORN, not MS_BORN...
msdos_rmdir(): kill BS comment
remove rpc_rmdir()
fs: avoid fdput() after failed fdget() in vfs_dedupe_file_range()
Diffstat (limited to 'Documentation/filesystems/Locking')
-rw-r--r-- | Documentation/filesystems/Locking | 43 |
1 files changed, 24 insertions, 19 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index 75d2d57e2c44..15853d522941 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -69,31 +69,31 @@ prototypes: locking rules: all may block - i_mutex(inode) -lookup: yes -create: yes -link: yes (both) -mknod: yes -symlink: yes -mkdir: yes -unlink: yes (both) -rmdir: yes (both) (see below) -rename: yes (all) (see below) + i_rwsem(inode) +lookup: shared +create: exclusive +link: exclusive (both) +mknod: exclusive +symlink: exclusive +mkdir: exclusive +unlink: exclusive (both) +rmdir: exclusive (both)(see below) +rename: exclusive (all) (see below) readlink: no get_link: no -setattr: yes +setattr: exclusive permission: no (may not block if called in rcu-walk mode) get_acl: no getattr: no listxattr: no fiemap: no update_time: no -atomic_open: yes +atomic_open: exclusive tmpfile: no - Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_mutex on -victim. + Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_rwsem + exclusive on victim. cross-directory ->rename() has (per-superblock) ->s_vfs_rename_sem. See Documentation/filesystems/directory-locking for more detailed discussion @@ -111,10 +111,10 @@ prototypes: locking rules: all may block - i_mutex(inode) + i_rwsem(inode) list: no get: no -set: yes +set: exclusive --------------------------- super_operations --------------------------- prototypes: @@ -217,14 +217,14 @@ prototypes: locking rules: All except set_page_dirty and freepage may block - PageLocked(page) i_mutex + PageLocked(page) i_rwsem writepage: yes, unlocks (see below) readpage: yes, unlocks writepages: set_page_dirty no readpages: -write_begin: locks the page yes -write_end: yes, unlocks yes +write_begin: locks the page exclusive +write_end: yes, unlocks exclusive bmap: invalidatepage: yes releasepage: yes @@ -439,6 +439,7 @@ prototypes: ssize_t (*read_iter) (struct kiocb *, struct iov_iter *); ssize_t (*write_iter) (struct kiocb *, struct iov_iter *); int (*iterate) (struct file *, struct dir_context *); + int (*iterate_shared) (struct file *, struct dir_context *); unsigned int (*poll) (struct file *, struct poll_table_struct *); long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long); long (*compat_ioctl) (struct file *, unsigned int, unsigned long); @@ -480,6 +481,10 @@ mutex or just to use i_size_read() instead. Note: this does not protect the file->f_pos against concurrent modifications since this is something the userspace has to take care about. +->iterate() is called with i_rwsem exclusive. + +->iterate_shared() is called with i_rwsem at least shared. + ->fasync() is responsible for maintaining the FASYNC bit in filp->f_flags. Most instances call fasync_helper(), which does that maintenance, so it's not normally something one needs to worry about. Return values > 0 will be |