litmus-rt.git - The LITMUS^RT kernel.

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The LITMUS^RT kernel.

Bjoern Brandenburg

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path: root/fs/jfs/namei.c

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fs/jfs/namei.c

1 files changed, 3 insertions, 0 deletions


diff --git a/fs/jfs/namei.c b/fs/jfs/namei.c index 0569daca86ad..865df16a6cf3 100644 --- a/fs/jfs/namei.c +++ b/fs/jfs/namei.c
@@ -1097,6 +1097,9 @@ static int jfs_rename(struct inode old_dir, struct dentry old_dentry,
1097	jfs_info("jfs_rename: %s %s", old_dentry->d_name.name,	1097	jfs_info("jfs_rename: %s %s", old_dentry->d_name.name,
1098	new_dentry->d_name.name);	1098	new_dentry->d_name.name);
1099		1099
		1100	if (new_dentry->d_inode && S_ISDIR(new_dentry->d_inode->i_mode))
		1101	dentry_unhash(new_dentry);
		1102
1100	dquot_initialize(old_dir);	1103	dquot_initialize(old_dir);
1101	dquot_initialize(new_dir);	1104	dquot_initialize(new_dir);
1102		1105

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/*
 * fs/direct-io.c
 *
 * Copyright (C) 2002, Linus Torvalds.
 *
 * O_DIRECT
 *
 * 04Jul2002	akpm@zip.com.au
 *		Initial version
 * 11Sep2002	janetinc@us.ibm.com
 * 		added readv/writev support.
 * 29Oct2002	akpm@zip.com.au
 *		rewrote bio_add_page() support.
 * 30Oct2002	pbadari@us.ibm.com
 *		added support for non-aligned IO.
 * 06Nov2002	pbadari@us.ibm.com
 *		added asynchronous IO support.
 * 21Jul2003	nathans@sgi.com
 *		added IO completion notifier.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/bio.h>
#include <linux/wait.h>
#include <linux/err.h>
#include <linux/blkdev.h>
#include <linux/buffer_head.h>
#include <linux/rwsem.h>
#include <linux/uio.h>
#include <asm/atomic.h>

/*
 * How many user pages to map in one call to get_user_pages().  This determines
 * the size of a structure on the stack.
 */
#define DIO_PAGES	64

/*
 * This code generally works in units of "dio_blocks".  A dio_block is
 * somewhere between the hard sector size and the filesystem block size.  it
 * is determined on a per-invocation basis.   When talking to the filesystem
 * we need to convert dio_blocks to fs_blocks by scaling the dio_block quantity
 * down by dio->blkfactor.  Similarly, fs-blocksize quantities are converted
 * to bio_block quantities by shifting left by blkfactor.
 *
 * If blkfactor is zero then the user's request was aligned to the filesystem's
 * blocksize.
 *
 * lock_type is DIO_LOCKING for regular files on direct-IO-naive filesystems.
 * This determines whether we need to do the fancy locking which prevents
 * direct-IO from being able to read uninitialised disk blocks.  If its zero
 * (blockdev) this locking is not done, and if it is DIO_OWN_LOCKING i_mutex is
 * not held for the entire direct write (taken briefly, initially, during a
 * direct read though, but its never held for the duration of a direct-IO).
 */

struct dio {
	/* BIO submission state */
	struct bio *bio;		/* bio under assembly */
	struct inode *inode;
	int rw;
	loff_t i_size;			/* i_size when submitted */
	int lock_type;			/* doesn't change */
	unsigned blkbits;		/* doesn't change */
	unsigned blkfactor;		/* When we're using an alignment which
					   is finer than the filesystem's soft
					   blocksize, this specifies how much
					   finer.  blkfactor=2 means 1/4-block
					   alignment.  Does not change */
	unsigned start_zero_done;	/* flag: sub-blocksize zeroing has
					   been performed at the start of a
					   write */
	int pages_in_io;		/* approximate total IO pages */
	size_t	size;			/* total request size (doesn't change)*/
	sector_t block_in_file;		/* Current offset into the underlying
					   file in dio_block units. */
	unsigned blocks_available;	/* At block_in_file.  changes */
	sector_t final_block_in_request;/* doesn't change */
	unsigned first_block_in_page;	/* doesn't change, Used only once */
	int boundary;			/* prev block is at a boundary */
	int reap_counter;		/* rate limit reaping */
	get_block_t *get_block;		/* block mapping function */
	dio_iodone_t *end_io;		/* IO completion function */
	sector_t final_block_in_bio;	/* current final block in bio + 1 */
	sector_t next_block_for_io;	/* next block to be put under IO,
					   in dio_blocks units */
	struct buffer_head map_bh;	/* last get_block() result */

	/*
	 * Deferred addition of a page to the dio.  These variables are
	 * private to dio_send_cur_page(), submit_page_section() and
	 * dio_bio_add_page().
	 */
	struct page *cur_page;		/* The page */
	unsigned cur_page_offset;	/* Offset into it, in bytes */
	unsigned cur_page_len;		/* Nr of bytes at cur_page_offset */
	sector_t cur_page_block;	/* Where it starts */

	/*
	 * Page fetching state. These variables belong to dio_refill_pages().
	 */
	int curr_page;			/* changes */
	int total_pages;		/* doesn't change */
	unsigned long curr_user_address;/* changes */

	/*
	 * Page queue.  These variables belong to dio_refill_pages() and
	 * dio_get_page().
	 */
	struct page *pages[DIO_PAGES];	/* page buffer */
	unsigned head;			/* next page to process */
	unsigned tail;			/* last valid page + 1 */
	int page_errors;		/* errno from get_user_pages() */

	/* BIO completion state */
	spinlock_t bio_lock;		/* protects BIO fields below */
	unsigned long refcount;		/* direct_io_worker() and bios */
	struct bio *bio_list;		/* singly linked via bi_private */
	struct task_struct *waiter;	/* waiting task (NULL if none) */

	/* AIO related stuff */
	struct kiocb *iocb;		/* kiocb */
	int is_async;			/* is IO async ? */
	int io_error;			/* IO error in completion path */
	ssize_t result;                 /* IO result */
};

/*
 * How many pages are in the queue?
 */
static inline unsigned dio_pages_present(struct dio *dio)
{
	return dio->tail - dio->head;
}

/*
 * Go grab and pin some userspace pages.   Typically we'll get 64 at a time.
 */
static int dio_refill_pages(struct dio *dio)
{
	int ret;
	int nr_pages;

	nr_pages = min(dio->total_pages - dio->curr_page, DIO_PAGES);
	down_read(&current->mm->mmap_sem);
	ret = get_user_pages(
		current,			/* Task for fault acounting */
		current->mm,			/* whose pages? */
		dio->curr_user_address,		/* Where from? */
		nr_pages,			/* How many pages? */
		dio->rw == READ,		/* Write to memory? */
		0,				/* force (?) */
		&dio->pages[0],
		NULL);				/* vmas */
	up_read(&current->mm->mmap_sem);

	if (ret < 0 && dio->blocks_available && (dio->rw & WRITE)) {
		struct page *page = ZERO_PAGE(dio->curr_user_address);
		/*
		 * A memory fault, but the filesystem has some outstanding
		 * mapped blocks.  We need to use those blocks up to avoid
		 * leaking stale data in the file.
		 */
		if (dio->page_errors == 0)
			dio->page_errors = ret;
		page_cache_get(page);
		dio->pages[0] = page;
		dio->head = 0;
		dio->tail = 1;
		ret = 0;
		goto out;
	}

	if (ret >= 0) {
		dio->curr_user_address += ret * PAGE_SIZE;
		dio->curr_page += ret;
		dio->head = 0;
		dio->tail = ret;
		ret = 0;
	}
out:
	return ret;	
}

/*
 * Get another userspace page.  Returns an ERR_PTR on error.  Pages are
 * buffered inside the dio so that we can call get_user_pages() against a
 * decent number of pages, less frequently.  To provide nicer use of the
 * L1 cache.
 */
static struct page *dio_get_page(struct dio *dio)
{
	if (dio_pages_present(dio) == 0) {
		int ret;

		ret = dio_refill_pages(dio);
		if (ret)
			return ERR_PTR(ret);
		BUG_ON(dio_pages_present(dio) == 0);
	}
	return dio->pages[dio->head++];
}

/**
 * dio_complete() - called when all DIO BIO I/O has been completed
 * @offset: the byte offset in the file of the completed operation
 *
 * This releases locks as dictated by the locking type, lets interested parties
 * know that a DIO operation has completed, and calculates the resulting return
 * code for the operation.
 *
 * It lets the filesystem know if it registered an interest earlier via
 * get_block.  Pass the private field of the map buffer_head so that
 * filesystems can use it to hold additional state between get_block calls and
 * dio_complete.
 */
static int dio_complete(struct dio *dio, loff_t offset, int ret)
{
	ssize_t transferred = 0;

	/*
	 * AIO submission can race with bio completion to get here while
	 * expecting to have the last io completed by bio completion.
	 * In that case -EIOCBQUEUED is in fact not an error we want
	 * to preserve through this call.
	 */
	if (ret == -EIOCBQUEUED)
		ret = 0;

	if (dio->result) {
		transferred = dio->result;

		/* Check for short read case */
		if ((dio->rw == READ) && ((offset + transferred) > dio->i_size))
			transferred = dio->i_size - offset;
	}

	if (dio->end_io && dio->result)
		dio->end_io(dio->iocb, offset, transferred,


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