void (*put_super) (struct super_block *);
void (*write_super) (struct super_block *);
int (*sync_fs)(struct super_block *sb, int wait);
- void (*write_super_lockfs) (struct super_block *);
- void (*unlockfs) (struct super_block *);
+ int (*freeze_fs) (struct super_block *);
+ 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 *);
locking rules:
All may block.
- BKL s_lock s_umount
-alloc_inode: no no no
-destroy_inode: no
-dirty_inode: no (must not sleep)
-write_inode: no
-drop_inode: no !!!inode_lock!!!
-delete_inode: no
-put_super: yes yes no
-write_super: no yes read
-sync_fs: no no read
-write_super_lockfs: ?
-unlockfs: ?
-statfs: no no no
-remount_fs: yes yes maybe (see below)
-clear_inode: no
-umount_begin: yes no no
-show_options: no (vfsmount->sem)
-quota_read: no no no (see below)
-quota_write: no no no (see below)
-
-->remount_fs() will have the s_umount lock if it's already mounted.
+ None have BKL
+ s_umount
+alloc_inode:
+destroy_inode:
+dirty_inode: (must not sleep)
+write_inode:
+drop_inode: !!!inode_lock!!!
+delete_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:
+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.
->quota_read() and ->quota_write() functions are both guaranteed to
be the only ones operating on the quota file by the quota code (via
write_begin: no locks the page yes
write_end: no yes, unlocks yes
perform_write: no n/a yes
-bmap: yes
+bmap: no
invalidatepage: no yes
releasepage: no yes
direct_IO: no
};
locking rules:
- All except ->poll() may block.
+ All may block.
BKL
llseek: no (see below)
read: no
can and should be done using the internal locking with smaller critical areas).
Current worst offender is ext2_get_block()...
-->fasync() is a mess. This area needs a big cleanup and that will probably
-affect locking.
+->fasync() is called without BKL protection, and 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 mapped to
+zero in the VFS layer.
->readdir() and ->ioctl() on directories must be changed. Ideally we would
move ->readdir() to inode_operations and use a separate method for directory
void (*open)(struct vm_area_struct*);
void (*close)(struct vm_area_struct*);
int (*fault)(struct vm_area_struct*, struct vm_fault *);
- int (*page_mkwrite)(struct vm_area_struct *, struct page *);
+ int (*page_mkwrite)(struct vm_area_struct *, struct vm_fault *);
int (*access)(struct vm_area_struct *, unsigned long, void*, int, int);
locking rules:
BKL mmap_sem PageLocked(page)
open: no yes
close: no yes
-fault: no yes
-page_mkwrite: no yes no
+fault: no yes can return with page locked
+page_mkwrite: no yes can return with page locked
access: no yes
- ->page_mkwrite() is called when a previously read-only page is
-about to become writeable. The file system is responsible for
-protecting against truncate races. Once appropriate action has been
-taking to lock out truncate, the page range should be verified to be
-within i_size. The page mapping should also be checked that it is not
-NULL.
+ ->fault() is called when a previously not present pte is about
+to be faulted in. The filesystem must find and return the page associated
+with the passed in "pgoff" in the vm_fault structure. If it is possible that
+the page may be truncated and/or invalidated, then the filesystem must lock
+the page, then ensure it is not already truncated (the page lock will block
+subsequent truncate), and then return with VM_FAULT_LOCKED, and the page
+locked. The VM will unlock the page.
+
+ ->page_mkwrite() is called when a previously read-only pte is
+about to become writeable. The filesystem again must ensure that there are
+no truncate/invalidate races, and then return with the page locked. If
+the page has been truncated, the filesystem should not look up a new page
+like the ->fault() handler, but simply return with VM_FAULT_NOPAGE, which
+will cause the VM to retry the fault.
->access() is called when get_user_pages() fails in
acces_process_vm(), typically used to debug a process through
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff