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-rw-r--r--Documentation/filesystems/Locking30
1 files changed, 13 insertions, 17 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 96d4293607e..2db4283efa8 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -92,8 +92,8 @@ prototypes:
void (*destroy_inode)(struct inode *);
void (*dirty_inode) (struct inode *);
int (*write_inode) (struct inode *, int);
- void (*drop_inode) (struct inode *);
- void (*delete_inode) (struct inode *);
+ int (*drop_inode) (struct inode *);
+ void (*evict_inode) (struct inode *);
void (*put_super) (struct super_block *);
void (*write_super) (struct super_block *);
int (*sync_fs)(struct super_block *sb, int wait);
@@ -101,14 +101,13 @@ prototypes:
int (*unfreeze_fs) (struct super_block *);
int (*statfs) (struct dentry *, struct kstatfs *);
int (*remount_fs) (struct super_block *, int *, char *);
- void (*clear_inode) (struct inode *);
void (*umount_begin) (struct super_block *);
int (*show_options)(struct seq_file *, struct vfsmount *);
ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);
ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);
locking rules:
- All may block.
+ All may block [not true, see below]
None have BKL
s_umount
alloc_inode:
@@ -116,22 +115,25 @@ destroy_inode:
dirty_inode: (must not sleep)
write_inode:
drop_inode: !!!inode_lock!!!
-delete_inode:
+evict_inode:
put_super: write
write_super: read
sync_fs: read
freeze_fs: read
unfreeze_fs: read
-statfs: no
-remount_fs: maybe (see below)
-clear_inode:
+statfs: maybe(read) (see below)
+remount_fs: write
umount_begin: no
show_options: no (namespace_sem)
quota_read: no (see below)
quota_write: no (see below)
-->remount_fs() will have the s_umount exclusive lock if it's already mounted.
-When called from get_sb_single, it does NOT have the s_umount lock.
+->statfs() has s_umount (shared) when called by ustat(2) (native or
+compat), but that's an accident of bad API; s_umount is used to pin
+the superblock down when we only have dev_t given us by userland to
+identify the superblock. Everything else (statfs(), fstatfs(), etc.)
+doesn't hold it when calling ->statfs() - superblock is pinned down
+by resolving the pathname passed to syscall.
->quota_read() and ->quota_write() functions are both guaranteed to
be the only ones operating on the quota file by the quota code (via
dqio_sem) (unless an admin really wants to screw up something and
@@ -372,8 +374,6 @@ prototypes:
ssize_t (*aio_write) (struct kiocb *, const struct iovec *, unsigned long, loff_t);
int (*readdir) (struct file *, void *, filldir_t);
unsigned int (*poll) (struct file *, struct poll_table_struct *);
- int (*ioctl) (struct inode *, struct file *, unsigned int,
- unsigned long);
long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
int (*mmap) (struct file *, struct vm_area_struct *);
@@ -407,8 +407,7 @@ write: no
aio_write: no
readdir: no
poll: no
-ioctl: yes (see below)
-unlocked_ioctl: no (see below)
+unlocked_ioctl: no
compat_ioctl: no
mmap: no
open: no
@@ -451,9 +450,6 @@ move ->readdir() to inode_operations and use a separate method for directory
anything that resembles union-mount we won't have a struct file for all
components. And there are other reasons why the current interface is a mess...
-->ioctl() on regular files is superceded by the ->unlocked_ioctl() that
-doesn't take the BKL.
-
->read on directories probably must go away - we should just enforce -EISDIR
in sys_read() and friends.