7b7a8665ed
Add support to the core direct-io code to defer AIO completions to user context using a workqueue. This replaces opencoded and less efficient code in XFS and ext4 (we save a memory allocation for each direct IO) and will be needed to properly support O_(D)SYNC for AIO. The communication between the filesystem and the direct I/O code requires a new buffer head flag, which is a bit ugly but not avoidable until the direct I/O code stops abusing the buffer_head structure for communicating with the filesystems. Currently this creates a per-superblock unbound workqueue for these completions, which is taken from an earlier patch by Jan Kara. I'm not really convinced about this use and would prefer a "normal" global workqueue with a high concurrency limit, but this needs further discussion. JK: Fixed ext4 part, dynamic allocation of the workqueue. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
63 lines
2.3 KiB
C
63 lines
2.3 KiB
C
/*
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* Copyright (c) 2005-2006 Silicon Graphics, Inc.
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* All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it would be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef __XFS_AOPS_H__
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#define __XFS_AOPS_H__
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extern mempool_t *xfs_ioend_pool;
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/*
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* Types of I/O for bmap clustering and I/O completion tracking.
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*/
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enum {
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XFS_IO_DIRECT = 0, /* special case for direct I/O ioends */
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XFS_IO_DELALLOC, /* covers delalloc region */
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XFS_IO_UNWRITTEN, /* covers allocated but uninitialized data */
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XFS_IO_OVERWRITE, /* covers already allocated extent */
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};
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#define XFS_IO_TYPES \
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{ 0, "" }, \
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{ XFS_IO_DELALLOC, "delalloc" }, \
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{ XFS_IO_UNWRITTEN, "unwritten" }, \
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{ XFS_IO_OVERWRITE, "overwrite" }
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/*
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* xfs_ioend struct manages large extent writes for XFS.
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* It can manage several multi-page bio's at once.
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*/
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typedef struct xfs_ioend {
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struct xfs_ioend *io_list; /* next ioend in chain */
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unsigned int io_type; /* delalloc / unwritten */
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int io_error; /* I/O error code */
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atomic_t io_remaining; /* hold count */
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unsigned int io_isdirect : 1;/* direct I/O */
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struct inode *io_inode; /* file being written to */
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struct buffer_head *io_buffer_head;/* buffer linked list head */
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struct buffer_head *io_buffer_tail;/* buffer linked list tail */
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size_t io_size; /* size of the extent */
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xfs_off_t io_offset; /* offset in the file */
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struct work_struct io_work; /* xfsdatad work queue */
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struct xfs_trans *io_append_trans;/* xact. for size update */
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} xfs_ioend_t;
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extern const struct address_space_operations xfs_address_space_operations;
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extern int xfs_get_blocks(struct inode *, sector_t, struct buffer_head *, int);
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extern void xfs_count_page_state(struct page *, int *, int *);
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#endif /* __XFS_AOPS_H__ */
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