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7c6c5249f0
With two clients, each with NFSv3 mounts of the same directory, the sequence:
client1 client2
ls -l afile
echo hello there > afile
echo HELLO > afile
cat afile
will show
HELLO
there
because the O_TRUNC requested in the final 'echo' doesn't take effect.
This is because the "Negative dentry, just create a file" section in
lookup_open() assumes that the file *does* get created since the dentry
was negative, so it sets FMODE_CREATED, and this causes do_open() to
clear O_TRUNC and so the file doesn't get truncated.
Even mounting with -o lookupcache=none does not help as
nfs_neg_need_reval() always returns false if LOOKUP_CREATE is set.
This patch fixes the problem by providing an atomic_open inode operation
for NFSv3 (and v2). The code is largely the code from the branch in
lookup_open() when atomic_open is not provided. The significant change
is that the O_TRUNC flag is passed a new nfs_do_create() which add
'trunc' handling to nfs_create().
With this change we also optimise away an unnecessary LOOKUP before the
file is created.
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
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| acpi | ||
| asm-generic | ||
| clocksource | ||
| crypto | ||
| drm | ||
| dt-bindings | ||
| keys | ||
| kunit | ||
| kvm | ||
| linux | ||
| math-emu | ||
| media | ||
| memory | ||
| misc | ||
| net | ||
| pcmcia | ||
| ras | ||
| rdma | ||
| rv | ||
| scsi | ||
| soc | ||
| sound | ||
| target | ||
| trace | ||
| uapi | ||
| ufs | ||
| vdso | ||
| video | ||
| xen | ||