22905f775d
NFS needs to be able to distinguish between single-page ->writepage() calls and multipage ->writepages() calls. For the single-page writepage calls NFS can kick off the I/O within the context of ->writepage(). For multipage ->writepages calls, nfs_writepage() will leave the I/O pending and nfs_writepages() will kick off the I/O when it all has been queued up within NFS. Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
114 lines
3.3 KiB
C
114 lines
3.3 KiB
C
/*
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* include/linux/writeback.h.
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*/
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#ifndef WRITEBACK_H
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#define WRITEBACK_H
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struct backing_dev_info;
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extern spinlock_t inode_lock;
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extern struct list_head inode_in_use;
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extern struct list_head inode_unused;
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/*
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* Yes, writeback.h requires sched.h
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* No, sched.h is not included from here.
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*/
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static inline int task_is_pdflush(struct task_struct *task)
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{
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return task->flags & PF_FLUSHER;
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}
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#define current_is_pdflush() task_is_pdflush(current)
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/*
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* fs/fs-writeback.c
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*/
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enum writeback_sync_modes {
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WB_SYNC_NONE, /* Don't wait on anything */
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WB_SYNC_ALL, /* Wait on every mapping */
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WB_SYNC_HOLD, /* Hold the inode on sb_dirty for sys_sync() */
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};
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/*
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* A control structure which tells the writeback code what to do. These are
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* always on the stack, and hence need no locking. They are always initialised
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* in a manner such that unspecified fields are set to zero.
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*/
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struct writeback_control {
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struct backing_dev_info *bdi; /* If !NULL, only write back this
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queue */
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enum writeback_sync_modes sync_mode;
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unsigned long *older_than_this; /* If !NULL, only write back inodes
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older than this */
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long nr_to_write; /* Write this many pages, and decrement
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this for each page written */
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long pages_skipped; /* Pages which were not written */
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/*
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* For a_ops->writepages(): is start or end are non-zero then this is
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* a hint that the filesystem need only write out the pages inside that
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* byterange. The byte at `end' is included in the writeout request.
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*/
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loff_t start;
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loff_t end;
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unsigned nonblocking:1; /* Don't get stuck on request queues */
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unsigned encountered_congestion:1; /* An output: a queue is full */
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unsigned for_kupdate:1; /* A kupdate writeback */
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unsigned for_reclaim:1; /* Invoked from the page allocator */
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unsigned for_writepages:1; /* This is a writepages() call */
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};
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/*
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* fs/fs-writeback.c
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*/
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void writeback_inodes(struct writeback_control *wbc);
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void wake_up_inode(struct inode *inode);
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int inode_wait(void *);
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void sync_inodes_sb(struct super_block *, int wait);
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void sync_inodes(int wait);
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/* writeback.h requires fs.h; it, too, is not included from here. */
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static inline void wait_on_inode(struct inode *inode)
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{
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might_sleep();
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wait_on_bit(&inode->i_state, __I_LOCK, inode_wait,
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TASK_UNINTERRUPTIBLE);
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}
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/*
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* mm/page-writeback.c
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*/
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int wakeup_pdflush(long nr_pages);
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void laptop_io_completion(void);
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void laptop_sync_completion(void);
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void throttle_vm_writeout(void);
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/* These are exported to sysctl. */
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extern int dirty_background_ratio;
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extern int vm_dirty_ratio;
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extern int dirty_writeback_centisecs;
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extern int dirty_expire_centisecs;
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extern int block_dump;
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extern int laptop_mode;
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struct ctl_table;
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struct file;
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int dirty_writeback_centisecs_handler(struct ctl_table *, int, struct file *,
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void __user *, size_t *, loff_t *);
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void page_writeback_init(void);
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void balance_dirty_pages_ratelimited(struct address_space *mapping);
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int pdflush_operation(void (*fn)(unsigned long), unsigned long arg0);
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int do_writepages(struct address_space *mapping, struct writeback_control *wbc);
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int sync_page_range(struct inode *inode, struct address_space *mapping,
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loff_t pos, size_t count);
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/* pdflush.c */
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extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
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read-only. */
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#endif /* WRITEBACK_H */
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