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xfs: move the dio write relocking out of xfs_ilock_for_iomap

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About half of xfs_ilock_for_iomap deals with a special case for direct
I/O writes to COW files that need to take the ilock exclusively.  Move
this code into the one callers that cares and simplify
xfs_ilock_for_iomap.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
This commit is contained in:
Christoph Hellwig 2024-06-23 07:44:26 +02:00 committed by Chandan Babu R
parent 0c7fcdb6d0
commit 8626b67acf
1 changed files with 34 additions and 37 deletions
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71
fs/xfs/xfs_iomap.c
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@ -717,53 +717,30 @@ imap_needs_cow(
return true;
}
/*
* Extents not yet cached requires exclusive access, don't block for
* IOMAP_NOWAIT.
*
* This is basically an opencoded xfs_ilock_data_map_shared() call, but with
* support for IOMAP_NOWAIT.
*/
static int
xfs_ilock_for_iomap(
struct xfs_inode *ip,
unsigned flags,
unsigned *lockmode)
{
unsigned int mode = *lockmode;
bool is_write = flags & (IOMAP_WRITE | IOMAP_ZERO);
/*
* COW writes may allocate delalloc space or convert unwritten COW
* extents, so we need to make sure to take the lock exclusively here.
*/
if (xfs_is_cow_inode(ip) && is_write)
mode = XFS_ILOCK_EXCL;
/*
* Extents not yet cached requires exclusive access, don't block. This
* is an opencoded xfs_ilock_data_map_shared() call but with
* non-blocking behaviour.
*/
if (xfs_need_iread_extents(&ip->i_df)) {
if (flags & IOMAP_NOWAIT)
return -EAGAIN;
mode = XFS_ILOCK_EXCL;
}
relock:
if (flags & IOMAP_NOWAIT) {
if (!xfs_ilock_nowait(ip, mode))
if (xfs_need_iread_extents(&ip->i_df))
return -EAGAIN;
if (!xfs_ilock_nowait(ip, *lockmode))
return -EAGAIN;
} else {
xfs_ilock(ip, mode);
if (xfs_need_iread_extents(&ip->i_df))
*lockmode = XFS_ILOCK_EXCL;
xfs_ilock(ip, *lockmode);
}
/*
* The reflink iflag could have changed since the earlier unlocked
* check, so if we got ILOCK_SHARED for a write and but we're now a
* reflink inode we have to switch to ILOCK_EXCL and relock.
*/
if (mode == XFS_ILOCK_SHARED && is_write && xfs_is_cow_inode(ip)) {
xfs_iunlock(ip, mode);
mode = XFS_ILOCK_EXCL;
goto relock;
}
*lockmode = mode;
return 0;
}
@ -801,7 +778,7 @@ xfs_direct_write_iomap_begin(
int nimaps = 1, error = 0;
bool shared = false;
u16 iomap_flags = 0;
unsigned int lockmode = XFS_ILOCK_SHARED;
unsigned int lockmode;
u64 seq;
ASSERT(flags & (IOMAP_WRITE | IOMAP_ZERO));
@ -817,10 +794,30 @@ xfs_direct_write_iomap_begin(
if (offset + length > i_size_read(inode))
iomap_flags |= IOMAP_F_DIRTY;
/*
* COW writes may allocate delalloc space or convert unwritten COW
* extents, so we need to make sure to take the lock exclusively here.
*/
if (xfs_is_cow_inode(ip))
lockmode = XFS_ILOCK_EXCL;
else
lockmode = XFS_ILOCK_SHARED;
relock:
error = xfs_ilock_for_iomap(ip, flags, &lockmode);
if (error)
return error;
/*
* The reflink iflag could have changed since the earlier unlocked
* check, check if it again and relock if needed.
*/
if (xfs_is_cow_inode(ip) && lockmode == XFS_ILOCK_SHARED) {
xfs_iunlock(ip, lockmode);
lockmode = XFS_ILOCK_EXCL;
goto relock;
}
error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb, &imap,
&nimaps, 0);
if (error)