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772430dd67
Various disk controllers require their buffers to be aligned to a
cache-line size (128 bytes). For buffers allocated in structures,
ensure that they are 128-byte aligned. Use aligned_malloc to allocate
memory to ensure that the returned memory is 128-byte aligned.
While we are here, we replace the dynamically allocated inode buffer
with a buffer allocated in the uufsd structure just as the superblock
and cylinder group buffers do.
This can be removed if/when the kernel is fixed. Because this problem
has existed on one I/O subsystem or another since the 1990's, we
are probably stuck with dealing with it forever.
The problem most recent showed up in Azure, see:
https://reviews.freebsd.org/D41728
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=267654
Before these fixes were applied, it was confirmed that the changes
in this commit also fixed the issue in Azure.
Reviewed-by: Warner Losh, kib
Tested-by: Souradeep Chakrabarti of Microsoft (earlier version)
PR: 267654
Differential Revision: https://reviews.freebsd.org/D41724
121 lines
2.6 KiB
Groff
121 lines
2.6 KiB
Groff
.\" Author: Juli Mallett <jmallett@FreeBSD.org>
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.\" Date: June 04, 2003
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.\" Description:
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.\" Manual page for libufs functions:
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.\" ufs_disk_close(3)
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.\" ufs_disk_fillout(3)
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.\" ufs_disk_fillout_blank(3)
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.\" ufs_disk_write(3)
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.\"
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.\" This file is in the public domain.
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.\"
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.Dd November 17, 2023
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.Dt UFS_DISK_CLOSE 3
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.Os
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.Sh NAME
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.Nm ufs_disk_close ,
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.Nm ufs_disk_fillout ,
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.Nm ufs_disk_fillout_blank ,
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.Nm ufs_disk_write
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.Nd open and close userland UFS disks
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.Sh LIBRARY
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.Lb libufs
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.Sh SYNOPSIS
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.In sys/param.h
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.In sys/mount.h
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.In ufs/ufs/ufsmount.h
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.In ufs/ufs/dinode.h
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.In ufs/ffs/fs.h
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.In libufs.h
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.Ft int
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.Fn ufs_disk_close "struct uufsd *disk"
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.Ft int
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.Fn ufs_disk_fillout "struct uufsd *disk" "const char *name"
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.Ft int
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.Fn ufs_disk_fillout_blank "struct uufsd *disk" "const char *name"
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.Ft int
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.Fn ufs_disk_write "struct uufsd *disk"
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.Sh DESCRIPTION
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The
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.Fn ufs_disk_close
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function closes a disk and frees internal memory related to it.
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It does not free the
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.Fa disk
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structure.
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.Pp
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The
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.Fn ufs_disk_fillout
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and
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.Fn ufs_disk_fillout_blank
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functions open a disk specified by
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.Fa name
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and populate the structure pointed to by
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.Fa disk .
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The structure referenced by the
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.Fa disk
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pointer must be aligned to at least the alignment specified by
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.Dv LIBUFS_ALIGN
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that is defined in the
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.Lb libufs.h
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header file.
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The disk is opened read-only.
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The specified
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.Fa name
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may be either a mountpoint, a device name or a filesystem image.
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The
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.Fn ufs_disk_fillout
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function assumes there is a valid superblock and will fail if not,
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whereas the
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.Fn ufs_disk_fillout_blank
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function makes no assumptions of that sort.
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.Pp
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The
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.Fn ufs_disk_write
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function attempts to re-open a disk as writable if it is not currently.
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.Sh ERRORS
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The function
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.Fn ufs_disk_close
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has no failure points.
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.Pp
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The function
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.Fn ufs_disk_fillout
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may fail for any of the reasons
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.Fn ufs_disk_fillout_blank
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might, as well as for any reason
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.Xr sbread 3
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might.
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.Pp
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The
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.Fn ufs_disk_fillout_blank
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may fail and set
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.Va errno
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for any of the errors specified for the library functions
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.Xr open 2 ,
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.Xr strdup 3 .
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Additionally, it may follow the
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.Xr libufs 3
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error methodologies in situations where no device could be found to
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open.
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.Pp
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The function
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.Fn ufs_disk_write
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may fail and set
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.Va errno
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for any of the errors specified for the library functions
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.Xr open 2
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and
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.Xr stat 2 .
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Namely, it will fail if the disk in question may not be written to.
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.Sh SEE ALSO
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.Xr open 2 ,
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.Xr getfsfile 3 ,
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.Xr libufs 3 ,
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.Xr sbread 3
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.Sh HISTORY
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These functions first appeared as part of
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.Xr libufs 3
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in
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.Fx 5.0 .
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.Sh AUTHORS
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.An Juli Mallett Aq Mt jmallett@FreeBSD.org
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