diff options
Diffstat (limited to 'include/linux/fs.h')
| -rw-r--r-- | include/linux/fs.h | 168 |
1 files changed, 153 insertions, 15 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index 8fabb037a48d..38dba16c4176 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -165,6 +165,8 @@ struct inodes_stat_t { #define READ 0 #define WRITE RW_MASK #define READA RWA_MASK +#define KERNEL_READ (READ|REQ_KERNEL) +#define KERNEL_WRITE (WRITE|REQ_KERNEL) #define READ_SYNC (READ | REQ_SYNC) #define WRITE_SYNC (WRITE | REQ_SYNC | REQ_NOIDLE) @@ -412,6 +414,7 @@ struct inodes_stat_t { #include <linux/shrinker.h> #include <linux/migrate_mode.h> #include <linux/uidgid.h> +#include <linux/lockdep.h> #include <asm/byteorder.h> @@ -427,6 +430,7 @@ struct kstatfs; struct vm_area_struct; struct vfsmount; struct cred; +struct swap_info_struct; extern void __init inode_init(void); extern void __init inode_init_early(void); @@ -437,6 +441,8 @@ extern unsigned long get_max_files(void); extern int sysctl_nr_open; extern struct inodes_stat_t inodes_stat; extern int leases_enable, lease_break_time; +extern int sysctl_protected_symlinks; +extern int sysctl_protected_hardlinks; struct buffer_head; typedef int (get_block_t)(struct inode *inode, sector_t iblock, @@ -636,6 +642,11 @@ struct address_space_operations { int (*is_partially_uptodate) (struct page *, read_descriptor_t *, unsigned long); int (*error_remove_page)(struct address_space *, struct page *); + + /* swapfile support */ + int (*swap_activate)(struct swap_info_struct *sis, struct file *file, + sector_t *span); + void (*swap_deactivate)(struct file *file); }; extern const struct address_space_operations empty_aops; @@ -1154,7 +1165,6 @@ struct lock_manager_operations { 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 *); int (*lm_change)(struct file_lock **, int); }; @@ -1163,9 +1173,10 @@ struct lock_manager { struct list_head list; }; -void locks_start_grace(struct lock_manager *); +struct net; +void locks_start_grace(struct net *, struct lock_manager *); void locks_end_grace(struct lock_manager *); -int locks_in_grace(void); +int locks_in_grace(struct net *); /* that will die - we need it for nfs_lock_info */ #include <linux/nfs_fs_i.h> @@ -1437,6 +1448,8 @@ extern void f_delown(struct file *filp); extern pid_t f_getown(struct file *filp); extern int send_sigurg(struct fown_struct *fown); +struct mm_struct; + /* * Umount options */ @@ -1450,6 +1463,31 @@ extern int send_sigurg(struct fown_struct *fown); extern struct list_head super_blocks; extern spinlock_t sb_lock; +/* Possible states of 'frozen' field */ +enum { + SB_UNFROZEN = 0, /* FS is unfrozen */ + SB_FREEZE_WRITE = 1, /* Writes, dir ops, ioctls frozen */ + SB_FREEZE_PAGEFAULT = 2, /* Page faults stopped as well */ + SB_FREEZE_FS = 3, /* For internal FS use (e.g. to stop + * internal threads if needed) */ + SB_FREEZE_COMPLETE = 4, /* ->freeze_fs finished successfully */ +}; + +#define SB_FREEZE_LEVELS (SB_FREEZE_COMPLETE - 1) + +struct sb_writers { + /* Counters for counting writers at each level */ + struct percpu_counter counter[SB_FREEZE_LEVELS]; + wait_queue_head_t wait; /* queue for waiting for + writers / faults to finish */ + int frozen; /* Is sb frozen? */ + wait_queue_head_t wait_unfrozen; /* queue for waiting for + sb to be thawed */ +#ifdef CONFIG_DEBUG_LOCK_ALLOC + struct lockdep_map lock_map[SB_FREEZE_LEVELS]; +#endif +}; + struct super_block { struct list_head s_list; /* Keep this first */ dev_t s_dev; /* search index; _not_ kdev_t */ @@ -1497,8 +1535,7 @@ struct super_block { struct hlist_node s_instances; struct quota_info s_dquot; /* Diskquota specific options */ - int s_frozen; - wait_queue_head_t s_wait_unfrozen; + struct sb_writers s_writers; char s_id[32]; /* Informational name */ u8 s_uuid[16]; /* UUID */ @@ -1553,14 +1590,117 @@ extern struct timespec current_fs_time(struct super_block *sb); /* * Snapshotting support. */ -enum { - SB_UNFROZEN = 0, - SB_FREEZE_WRITE = 1, - SB_FREEZE_TRANS = 2, -}; -#define vfs_check_frozen(sb, level) \ - wait_event((sb)->s_wait_unfrozen, ((sb)->s_frozen < (level))) +void __sb_end_write(struct super_block *sb, int level); +int __sb_start_write(struct super_block *sb, int level, bool wait); + +/** + * sb_end_write - drop write access to a superblock + * @sb: the super we wrote to + * + * Decrement number of writers to the filesystem. Wake up possible waiters + * wanting to freeze the filesystem. + */ +static inline void sb_end_write(struct super_block *sb) +{ + __sb_end_write(sb, SB_FREEZE_WRITE); +} + +/** + * sb_end_pagefault - drop write access to a superblock from a page fault + * @sb: the super we wrote to + * + * Decrement number of processes handling write page fault to the filesystem. + * Wake up possible waiters wanting to freeze the filesystem. + */ +static inline void sb_end_pagefault(struct super_block *sb) +{ + __sb_end_write(sb, SB_FREEZE_PAGEFAULT); +} + +/** + * sb_end_intwrite - drop write access to a superblock for internal fs purposes + * @sb: the super we wrote to + * + * Decrement fs-internal number of writers to the filesystem. Wake up possible + * waiters wanting to freeze the filesystem. + */ +static inline void sb_end_intwrite(struct super_block *sb) +{ + __sb_end_write(sb, SB_FREEZE_FS); +} + +/** + * sb_start_write - get write access to a superblock + * @sb: the super we write to + * + * When a process wants to write data or metadata to a file system (i.e. dirty + * a page or an inode), it should embed the operation in a sb_start_write() - + * sb_end_write() pair to get exclusion against file system freezing. This + * function increments number of writers preventing freezing. If the file + * system is already frozen, the function waits until the file system is + * thawed. + * + * Since freeze protection behaves as a lock, users have to preserve + * ordering of freeze protection and other filesystem locks. Generally, + * freeze protection should be the outermost lock. In particular, we have: + * + * sb_start_write + * -> i_mutex (write path, truncate, directory ops, ...) + * -> s_umount (freeze_super, thaw_super) + */ +static inline void sb_start_write(struct super_block *sb) +{ + __sb_start_write(sb, SB_FREEZE_WRITE, true); +} + +static inline int sb_start_write_trylock(struct super_block *sb) +{ + return __sb_start_write(sb, SB_FREEZE_WRITE, false); +} + +/** + * sb_start_pagefault - get write access to a superblock from a page fault + * @sb: the super we write to + * + * When a process starts handling write page fault, it should embed the + * operation into sb_start_pagefault() - sb_end_pagefault() pair to get + * exclusion against file system freezing. This is needed since the page fault + * is going to dirty a page. This function increments number of running page + * faults preventing freezing. If the file system is already frozen, the + * function waits until the file system is thawed. + * + * Since page fault freeze protection behaves as a lock, users have to preserve + * ordering of freeze protection and other filesystem locks. It is advised to + * put sb_start_pagefault() close to mmap_sem in lock ordering. Page fault + * handling code implies lock dependency: + * + * mmap_sem + * -> sb_start_pagefault + */ +static inline void sb_start_pagefault(struct super_block *sb) +{ + __sb_start_write(sb, SB_FREEZE_PAGEFAULT, true); +} + +/* + * sb_start_intwrite - get write access to a superblock for internal fs purposes + * @sb: the super we write to + * + * This is the third level of protection against filesystem freezing. It is + * free for use by a filesystem. The only requirement is that it must rank + * below sb_start_pagefault. + * + * For example filesystem can call sb_start_intwrite() when starting a + * transaction which somewhat eases handling of freezing for internal sources + * of filesystem changes (internal fs threads, discarding preallocation on file + * close, etc.). + */ +static inline void sb_start_intwrite(struct super_block *sb) +{ + __sb_start_write(sb, SB_FREEZE_FS, true); +} + extern bool inode_owner_or_capable(const struct inode *inode); @@ -1884,6 +2024,7 @@ struct file_system_type { struct lock_class_key s_lock_key; struct lock_class_key s_umount_key; struct lock_class_key s_vfs_rename_key; + struct lock_class_key s_writers_key[SB_FREEZE_LEVELS]; struct lock_class_key i_lock_key; struct lock_class_key i_mutex_key; @@ -2326,9 +2467,6 @@ static inline void i_readcount_inc(struct inode *inode) } #endif extern int do_pipe_flags(int *, int); -extern struct file *create_read_pipe(struct file *f, int flags); -extern struct file *create_write_pipe(int flags); -extern void free_write_pipe(struct file *); extern int kernel_read(struct file *, loff_t, char *, unsigned long); extern struct file * open_exec(const char *); |