b32f4c7ed8
This patch re-adds the ability to optionally run in buffered FILEIO mode
(eg: w/o O_DSYNC) for device backends in order to once again use the
Linux buffered cache as a write-back storage mechanism.
This logic was originally dropped with mainline v3.5-rc commit:
commit a4dff3043c
Author: Nicholas Bellinger <nab@linux-iscsi.org>
Date: Wed May 30 16:25:41 2012 -0700
target/file: Use O_DSYNC by default for FILEIO backends
This difference with this patch is that fd_create_virtdevice() now
forces the explicit setting of emulate_write_cache=1 when buffered FILEIO
operation has been enabled.
(v2: Switch to FDBD_HAS_BUFFERED_IO_WCE + add more detailed
comment as requested by hch)
Reported-by: Ferry <iscsitmp@bananateam.nl>
Cc: Christoph Hellwig <hch@lst.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
40 lines
941 B
C
40 lines
941 B
C
#ifndef TARGET_CORE_FILE_H
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#define TARGET_CORE_FILE_H
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#define FD_VERSION "4.0"
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#define FD_MAX_DEV_NAME 256
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#define FD_DEVICE_QUEUE_DEPTH 32
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#define FD_MAX_DEVICE_QUEUE_DEPTH 128
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#define FD_BLOCKSIZE 512
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#define FD_MAX_SECTORS 1024
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#define RRF_EMULATE_CDB 0x01
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#define RRF_GOT_LBA 0x02
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#define FBDF_HAS_PATH 0x01
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#define FBDF_HAS_SIZE 0x02
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#define FDBD_HAS_BUFFERED_IO_WCE 0x04
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struct fd_dev {
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u32 fbd_flags;
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unsigned char fd_dev_name[FD_MAX_DEV_NAME];
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/* Unique Ramdisk Device ID in Ramdisk HBA */
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u32 fd_dev_id;
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/* Number of SG tables in sg_table_array */
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u32 fd_table_count;
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u32 fd_queue_depth;
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u32 fd_block_size;
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unsigned long long fd_dev_size;
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struct file *fd_file;
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/* FILEIO HBA device is connected to */
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struct fd_host *fd_host;
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} ____cacheline_aligned;
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struct fd_host {
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u32 fd_host_dev_id_count;
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/* Unique FILEIO Host ID */
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u32 fd_host_id;
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} ____cacheline_aligned;
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#endif /* TARGET_CORE_FILE_H */
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