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ext4: fix ext4_dax_read/write inode locking sequence for IOCB_NOWAIT
Apparently our current rwsem code doesn't like doing the trylock, then
lock for real scheme. So change our dax read/write methods to just do the
trylock for the RWF_NOWAIT case.
This seems to fix AIM7 regression in some scalable filesystems upto ~25%
in some cases. Claimed in commit 942491c9e6
("xfs: fix AIM7 regression")
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
Tested-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/20191212055557.11151-2-riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
parent
46cf053efe
commit
f629afe336
1 changed files with 6 additions and 4 deletions
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@ -88,9 +88,10 @@ static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
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struct inode *inode = file_inode(iocb->ki_filp);
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ssize_t ret;
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if (!inode_trylock_shared(inode)) {
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if (iocb->ki_flags & IOCB_NOWAIT)
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if (iocb->ki_flags & IOCB_NOWAIT) {
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if (!inode_trylock_shared(inode))
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return -EAGAIN;
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} else {
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inode_lock_shared(inode);
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}
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/*
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@ -487,9 +488,10 @@ ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
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bool extend = false;
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struct inode *inode = file_inode(iocb->ki_filp);
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if (!inode_trylock(inode)) {
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if (iocb->ki_flags & IOCB_NOWAIT)
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if (iocb->ki_flags & IOCB_NOWAIT) {
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if (!inode_trylock(inode))
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return -EAGAIN;
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} else {
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inode_lock(inode);
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}
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