On Wed, 11 Apr 2007 18:55:14 +0200, [EMAIL PROTECTED] <[EMAIL PROTECTED]>
wrote:
In reviewing the following code, one would conclude that while running
fssnap, the source filesystem is set to read only until the bitmap has
been created:
http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/common/io/fssnap.c
Is this to be expected?
Yes for UFS, for the duration of setting up the candidate bitmaps we write
lock
the source file system, once we populated the incore candidate bitmaps
we unlock it.
There is nothing within the man pages to indicate that this may occur.
fssnap_ufs(1M)
NOTES
These conditions result in fssnap being unable to write lock
the file system prior to performing the snapshot.
"When a snapshot is to be created, the user utility will send an ioctl
to the control device of the driver half specifying the file system to
be snapshotted, the file descriptor of a backing-store file which is
used to hold old data before it is overwritten, and other snapshot
parameters. This ioctl is passed on to the file system specified in the
original ioctl request. The file system is expected to be able to flush
everything out to make the file system consistent and lock it to ensure
no changes occur while the snapshot is being created..........Once the
candidate bitmap is populated with fssnap_set_candidate(), the file
system calls fssnap_create_done() to complete the snapshot creation and
unlock the snapshot. The file system may now be unlocked and
modifications to it resumed."
---
frankB
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