diff options
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/Locking | 30 | ||||
| -rw-r--r-- | Documentation/filesystems/porting | 21 | ||||
| -rw-r--r-- | Documentation/filesystems/vfs.txt | 35 |
3 files changed, 66 insertions, 20 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index 8e2da1e06e3..0f103e39b4f 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -9,7 +9,7 @@ be able to use diff(1). --------------------------- dentry_operations -------------------------- prototypes: - int (*d_revalidate)(struct dentry *, struct nameidata *); + int (*d_revalidate)(struct dentry *, unsigned int); int (*d_hash)(const struct dentry *, const struct inode *, struct qstr *); int (*d_compare)(const struct dentry *, const struct inode *, @@ -37,9 +37,8 @@ d_manage: no no yes (ref-walk) maybe --------------------------- inode_operations --------------------------- prototypes: - int (*create) (struct inode *,struct dentry *,umode_t, struct nameidata *); - struct dentry * (*lookup) (struct inode *,struct dentry *, struct nameid -ata *); + int (*create) (struct inode *,struct dentry *,umode_t, bool); + struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int); int (*link) (struct dentry *,struct inode *,struct dentry *); int (*unlink) (struct inode *,struct dentry *); int (*symlink) (struct inode *,struct dentry *,const char *); @@ -62,6 +61,9 @@ ata *); int (*removexattr) (struct dentry *, const char *); int (*fiemap)(struct inode *, struct fiemap_extent_info *, u64 start, u64 len); 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); locking rules: all may block @@ -89,6 +91,7 @@ listxattr: no removexattr: yes fiemap: no update_time: no +atomic_open: yes Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_mutex on victim. @@ -135,8 +138,8 @@ evict_inode: put_super: write write_super: read sync_fs: read -freeze_fs: read -unfreeze_fs: read +freeze_fs: write +unfreeze_fs: write statfs: maybe(read) (see below) remount_fs: write umount_begin: no @@ -203,6 +206,8 @@ prototypes: int (*launder_page)(struct page *); int (*is_partially_uptodate)(struct page *, read_descriptor_t *, unsigned long); int (*error_remove_page)(struct address_space *, struct page *); + int (*swap_activate)(struct file *); + int (*swap_deactivate)(struct file *); locking rules: All except set_page_dirty and freepage may block @@ -226,6 +231,8 @@ migratepage: yes (both) launder_page: yes is_partially_uptodate: yes error_remove_page: yes +swap_activate: no +swap_deactivate: no ->write_begin(), ->write_end(), ->sync_page() and ->readpage() may be called from the request handler (/dev/loop). @@ -327,6 +334,15 @@ cleaned, or an error value if not. Note that in order to prevent the page getting mapped back in and redirtied, it needs to be kept locked across the entire operation. + ->swap_activate will be called with a non-zero argument on +files backing (non block device backed) swapfiles. A return value +of zero indicates success, in which case this file can be used for +backing swapspace. The swapspace operations will be proxied to the +address space operations. + + ->swap_deactivate() will be called in the sys_swapoff() +path after ->swap_activate() returned success. + ----------------------- file_lock_operations ------------------------------ prototypes: void (*fl_copy_lock)(struct file_lock *, struct file_lock *); @@ -343,7 +359,6 @@ prototypes: int (*lm_compare_owner)(struct file_lock *, struct file_lock *); void (*lm_notify)(struct file_lock *); /* unblock callback */ int (*lm_grant)(struct file_lock *, struct file_lock *, int); - void (*lm_release_private)(struct file_lock *); void (*lm_break)(struct file_lock *); /* break_lease callback */ int (*lm_change)(struct file_lock **, int); @@ -352,7 +367,6 @@ locking rules: lm_compare_owner: yes no lm_notify: yes no lm_grant: no no -lm_release_private: maybe no lm_break: yes no lm_change yes no diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting index 8c91d1057d9..2bef2b3843d 100644 --- a/Documentation/filesystems/porting +++ b/Documentation/filesystems/porting @@ -355,12 +355,10 @@ protects *all* the dcache state of a given dentry. via rcu-walk path walk (basically, if the file can have had a path name in the vfs namespace). - i_dentry and i_rcu share storage in a union, and the vfs expects -i_dentry to be reinitialized before it is freed, so an: - - INIT_LIST_HEAD(&inode->i_dentry); - -must be done in the RCU callback. + Even though i_dentry and i_rcu share storage in a union, we will +initialize the former in inode_init_always(), so just leave it alone in +the callback. It used to be necessary to clean it there, but not anymore +(starting at 3.2). -- [recommended] @@ -433,3 +431,14 @@ release it yourself. d_alloc_root() is gone, along with a lot of bugs caused by code misusing it. Replacement: d_make_root(inode). The difference is, d_make_root() drops the reference to inode if dentry allocation fails. + +-- +[mandatory] + The witch is dead! Well, 2/3 of it, anyway. ->d_revalidate() and +->lookup() do *not* take struct nameidata anymore; just the flags. +-- +[mandatory] + ->create() doesn't take struct nameidata *; unlike the previous +two, it gets "is it an O_EXCL or equivalent?" boolean argument. Note that +local filesystems can ignore tha argument - they are guaranteed that the +object doesn't exist. It's remote/distributed ones that might care... diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index efd23f48170..065aa2dc083 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -341,8 +341,8 @@ This describes how the VFS can manipulate an inode in your filesystem. As of kernel 2.6.22, the following members are defined: struct inode_operations { - int (*create) (struct inode *,struct dentry *, umode_t, struct nameidata *); - struct dentry * (*lookup) (struct inode *,struct dentry *, struct nameidata *); + int (*create) (struct inode *,struct dentry *, umode_t, bool); + struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int); int (*link) (struct dentry *,struct inode *,struct dentry *); int (*unlink) (struct inode *,struct dentry *); int (*symlink) (struct inode *,struct dentry *,const char *); @@ -364,6 +364,9 @@ struct inode_operations { ssize_t (*listxattr) (struct dentry *, char *, size_t); int (*removexattr) (struct dentry *, const char *); 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); }; Again, all methods are called without any locks being held, unless @@ -476,6 +479,14 @@ otherwise noted. an inode. If this is not defined the VFS will update the inode itself and call mark_inode_dirty_sync. + 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(). + The Address Space Object ======================== @@ -581,6 +592,8 @@ struct address_space_operations { int (*migratepage) (struct page *, struct page *); int (*launder_page) (struct page *); int (*error_remove_page) (struct mapping *mapping, struct page *page); + int (*swap_activate)(struct file *); + int (*swap_deactivate)(struct file *); }; writepage: called by the VM to write a dirty page to backing store. @@ -749,6 +762,16 @@ struct address_space_operations { Setting this implies you deal with pages going away under you, unless you have them locked or reference counts increased. + swap_activate: Called when swapon is used on a file to allocate + space if necessary and pin the block lookup information in + memory. A return value of zero indicates success, + in which case this file can be used to back swapspace. The + swapspace operations will be proxied to this address space's + ->swap_{out,in} methods. + + swap_deactivate: Called during swapoff on files where swap_activate + was successful. + The File Object =============== @@ -891,7 +914,7 @@ the VFS uses a default. As of kernel 2.6.22, the following members are defined: struct dentry_operations { - int (*d_revalidate)(struct dentry *, struct nameidata *); + int (*d_revalidate)(struct dentry *, unsigned int); int (*d_hash)(const struct dentry *, const struct inode *, struct qstr *); int (*d_compare)(const struct dentry *, const struct inode *, @@ -910,11 +933,11 @@ struct dentry_operations { dcache. Most filesystems leave this as NULL, because all their dentries in the dcache are valid - d_revalidate may be called in rcu-walk mode (nd->flags & LOOKUP_RCU). + d_revalidate may be called in rcu-walk mode (flags & LOOKUP_RCU). If in rcu-walk mode, the filesystem must revalidate the dentry without blocking or storing to the dentry, d_parent and d_inode should not be - used without care (because they can go NULL), instead nd->inode should - be used. + used without care (because they can change and, in d_inode case, even + become NULL under us). If a situation is encountered that rcu-walk cannot handle, return -ECHILD and it will be called again in ref-walk mode. |