From: Matthew Wilcox <willy@debian.org> Here's an update to Documentation/filesystems/Locking. Documentation/filesystems/Locking | 149 +++++++++++++++++++++++--------------- 1 files changed, 93 insertions(+), 56 deletions(-) diff -puN Documentation/filesystems/Locking~Locking-update Documentation/filesystems/Locking --- 25/Documentation/filesystems/Locking~Locking-update 2003-08-18 03:31:54.000000000 -0700 +++ 25-akpm/Documentation/filesystems/Locking 2003-08-18 03:31:54.000000000 -0700 @@ -28,8 +28,9 @@ d_iput: no no no yes --------------------------- inode_operations --------------------------- prototypes: - int (*create) (struct inode *,struct dentry *,int); - struct dentry * (*lookup) (struct inode *,struct dentry *); + int (*create) (struct inode *,struct dentry *,int, struct nameidata *); + struct dentry * (*lookup) (struct inode *,struct dentry *, struct nameid +ata *); int (*link) (struct dentry *,struct inode *,struct dentry *); int (*unlink) (struct inode *,struct dentry *); int (*symlink) (struct inode *,struct dentry *,const char *); @@ -38,13 +39,13 @@ prototypes: int (*mknod) (struct inode *,struct dentry *,int,dev_t); int (*rename) (struct inode *, struct dentry *, struct inode *, struct dentry *); - int (*readlink) (struct dentry *, char *,int); + int (*readlink) (struct dentry *, char __user *,int); int (*follow_link) (struct dentry *, struct nameidata *); void (*truncate) (struct inode *); - int (*permission) (struct inode *, int); + int (*permission) (struct inode *, int, struct nameidata *); int (*setattr) (struct dentry *, struct iattr *); int (*getattr) (struct vfsmount *, struct dentry *, struct kstat *); - int (*setxattr) (struct dentry *, const char *, void *, size_t, int); + int (*setxattr) (struct dentry *, const char *,const void *,size_t,int); ssize_t (*getxattr) (struct dentry *, const char *, void *, size_t); ssize_t (*listxattr) (struct dentry *, char *, size_t); int (*removexattr) (struct dentry *, const char *); @@ -85,42 +86,55 @@ of the locking scheme for directory oper --------------------------- super_operations --------------------------- prototypes: + struct inode *(*alloc_inode)(struct super_block *sb); + void (*destroy_inode)(struct inode *); void (*read_inode) (struct inode *); + void (*dirty_inode) (struct inode *); void (*write_inode) (struct inode *, int); void (*put_inode) (struct inode *); void (*drop_inode) (struct inode *); void (*delete_inode) (struct inode *); void (*put_super) (struct super_block *); void (*write_super) (struct super_block *); - int (*sync_fs) (struct super_block *sb, int wait); - int (*statfs) (struct super_block *, struct statfs *); + int (*sync_fs)(struct super_block *sb, int wait); + void (*write_super_lockfs) (struct super_block *); + void (*unlockfs) (struct super_block *); + int (*statfs) (struct super_block *, 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 *); locking rules: All may block. - BKL s_lock mount_sem -read_inode: yes (see below) -write_inode: no -put_inode: no -drop_inode: no !!!inode_lock!!! -delete_inode: no -clear_inode: no -put_super: yes yes maybe (see below) -write_super: no yes maybe (see below) -sync_fs: no no maybe (see below) -statfs: no no no -remount_fs: yes yes maybe (see below) -umount_begin: yes no maybe (see below) + BKL s_lock s_umount +alloc_inode: no no no +destroy_inode: no +read_inode: no (see below) +dirty_inode: no (must not sleep) +write_inode: no +put_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: no yes maybe (see below) +clear_inode: no +umount_begin: yes no no +show_options: no (vfsmount->sem) ->read_inode() is not a method - it's a callback used in iget(). -rules for mount_sem are not too nice - it is going to die and be replaced -by better scheme anyway. +->remount_fs() will have the s_umount lock if it's already mounted. +When called from get_sb_single, it does NOT have the s_umount lock. --------------------------- file_system_type --------------------------- prototypes: - struct super_block *(*get_sb) (struct file_system_type *, int, const char *, void *); + struct super_block *(*get_sb) (struct file_system_type *, int, + const char *, void *); void (*kill_sb) (struct super_block *); locking rules: may block BKL @@ -128,7 +142,7 @@ get_sb yes yes kill_sb yes yes ->get_sb() returns error or a locked superblock (exclusive on ->s_umount). -->kill_sb() takes a locked superblock, does all shutdown work on it, +->kill_sb() takes a write-locked superblock, does all shutdown work on it, unlocks and drops the reference. --------------------------- address_space_operations -------------------------- @@ -138,12 +152,15 @@ prototypes: int (*sync_page)(struct page *); int (*writepages)(struct address_space *, struct writeback_control *); int (*set_page_dirty)(struct page *page); + int (*readpages)(struct file *filp, struct address_space *mapping, + struct list_head *pages, unsigned nr_pages); int (*prepare_write)(struct file *, struct page *, unsigned, unsigned); int (*commit_write)(struct file *, struct page *, unsigned, unsigned); - int (*bmap)(struct address_space *, long); + sector_t (*bmap)(struct address_space *, sector_t); int (*invalidatepage) (struct page *, unsigned long); int (*releasepage) (struct page *, int); - int (*direct_IO)(int, struct inode *, struct kiobuf *, unsigned long, int); + int (*direct_IO)(int, struct kiocb *, const struct iovec *iov, + loff_t offset, unsigned long nr_segs); locking rules: All except set_page_dirty may block @@ -151,15 +168,16 @@ locking rules: BKL PageLocked(page) writepage: no yes, unlocks (see below) readpage: no yes, unlocks -readpages: no sync_page: no maybe writepages: no set_page_dirty no no +readpages: no prepare_write: no yes commit_write: no yes bmap: yes invalidatepage: no yes releasepage: no yes +direct_IO: no ->prepare_write(), ->commit_write(), ->sync_page() and ->readpage() may be called from the request handler (/dev/loop). @@ -253,8 +271,8 @@ prototypes: locking rules: BKL may block fl_notify: yes no -fl_insert: yes maybe -fl_remove: yes maybe +fl_insert: yes no +fl_remove: yes no Currently only NLM provides instances of this class. None of the them block. If you have out-of-tree instances - please, show up. Locking in that area will change. @@ -274,57 +292,75 @@ prototypes: int (*open) (struct inode *, struct file *); int (*release) (struct inode *, struct file *); int (*ioctl) (struct inode *, struct file *, unsigned, unsigned long); - int (*check_media_change) (kdev_t); - int (*revalidate) (kdev_t); + int (*media_changed) (struct gendisk *); + int (*revalidate_disk) (struct gendisk *); + locking rules: BKL bd_sem open: yes yes release: yes yes ioctl: yes no -check_media_change: yes no -revalidate: yes no +media_changed: no no +revalidate_disk: no no -The last two are called only from check_disk_change(). Prototypes are very -bad - as soon as we'll get disk_struct they will change (and methods will -become per-disk instead of per-partition). +The last two are called only from check_disk_change(). --------------------------- file_operations ------------------------------- prototypes: loff_t (*llseek) (struct file *, loff_t, int); - ssize_t (*read) (struct file *, char *, size_t, loff_t *); - ssize_t (*write) (struct file *, const char *, size_t, loff_t *); + ssize_t (*read) (struct file *, char __user *, size_t, loff_t *); + ssize_t (*aio_read) (struct kiocb *, char __user *, size_t, loff_t); + ssize_t (*write) (struct file *, const char __user *, size_t, loff_t *); + ssize_t (*aio_write) (struct kiocb *, const char __user *, size_t, + 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); + int (*ioctl) (struct inode *, struct file *, unsigned int, + unsigned long); int (*mmap) (struct file *, struct vm_area_struct *); int (*open) (struct inode *, struct file *); int (*flush) (struct file *); int (*release) (struct inode *, struct file *); int (*fsync) (struct file *, struct dentry *, int datasync); + int (*aio_fsync) (struct kiocb *, int datasync); int (*fasync) (int, struct file *, int); int (*lock) (struct file *, int, struct file_lock *); - ssize_t (*readv) (struct file *, const struct iovec *, unsigned long, loff_t *); - ssize_t (*writev) (struct file *, const struct iovec *, unsigned long, loff_t *); + ssize_t (*readv) (struct file *, const struct iovec *, unsigned long, + loff_t *); + ssize_t (*writev) (struct file *, const struct iovec *, unsigned long, + loff_t *); + ssize_t (*sendfile) (struct file *, loff_t *, size_t, read_actor_t, + void __user *); + ssize_t (*sendpage) (struct file *, struct page *, int, size_t, + loff_t *, int); + unsigned long (*get_unmapped_area)(struct file *, unsigned long, + unsigned long, unsigned long, unsigned long); }; locking rules: All except ->poll() may block. - BKL -llseek: yes (see below) -read: no -write: no -readdir: no -poll: no -ioctl: yes (see below) -mmap: no -open: maybe (see below) -flush: no -release: no -fsync: yes (see below) -fasync: yes (see below) -lock: yes -readv: no -writev: no + BKL +llseek: no (see below) +read: no +aio_read: no +write: no +aio_write: no +readdir: no +poll: no +ioctl: yes (see below) +mmap: no +open: maybe (see below) +flush: no +release: no +fsync: no (see below) +aio_fsync: no +fasync: yes (see below) +lock: yes +readv: no +writev: no +sendfile: no +sendpage: no +get_unmapped_area: no ->llseek() locking has moved from llseek to the individual llseek implementations. If your fs is not using generic_file_llseek, you _