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xfs: improve mapping type check in xfs_vm_writepage

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Currently we only refuse a "read-only" mapping for writing out
unwritten and delayed buffers, and refuse any other for overwrites.
Improve the checks to require delalloc mappings for delayed buffers,
and unwritten extent mappings for unwritten extents.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Alex Elder <aelder@sgi.com>
This commit is contained in:
Christoph Hellwig 2010-12-10 08:42:16 +00:00 • committed by Alex Elder
parent c9f71f5fc4
commit 85da94c6b4
1 changed files with 12 additions and 9 deletions
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21
fs/xfs/linux-2.6/xfs_aops.c
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@ -1082,17 +1082,17 @@ xfs_vm_writepage(
if (buffer_unwritten(bh) || buffer_delay(bh)) { if (buffer_unwritten(bh) || buffer_delay(bh)) {
int new_ioend = 0; int new_ioend = 0;
/*
* Make sure we don't use a read-only iomap
*/
if (flags == BMAPI_READ)
imap_valid = 0;
if (buffer_unwritten(bh)) { if (buffer_unwritten(bh)) {
type = IO_UNWRITTEN; if (type != IO_UNWRITTEN) {
type = IO_UNWRITTEN;
imap_valid = 0;
}
flags = BMAPI_WRITE | BMAPI_IGNSTATE; flags = BMAPI_WRITE | BMAPI_IGNSTATE;
} else if (buffer_delay(bh)) { } else if (buffer_delay(bh)) {
type = IO_DELAY; if (type != IO_DELAY) {
type = IO_DELAY;
imap_valid = 0;
}
flags = BMAPI_ALLOCATE; flags = BMAPI_ALLOCATE;
if (wbc->sync_mode == WB_SYNC_NONE) if (wbc->sync_mode == WB_SYNC_NONE)
@ -1128,8 +1128,11 @@ xfs_vm_writepage(
* That means it must already have extents allocated * That means it must already have extents allocated
* underneath it. Map the extent by reading it. * underneath it. Map the extent by reading it.
*/ */
if (!imap_valid || flags != BMAPI_READ) { if (flags != BMAPI_READ) {
flags = BMAPI_READ; flags = BMAPI_READ;
imap_valid = 0;
}
if (!imap_valid) {
size = xfs_probe_cluster(inode, page, bh, head); size = xfs_probe_cluster(inode, page, bh, head);
err = xfs_map_blocks(inode, offset, size, err = xfs_map_blocks(inode, offset, size,
&imap, flags); &imap, flags);