linux-dev/fs/9p, branch master

9p: Fix some kernel-doc comments

2022-07-02T09:52:21Z

Remove warnings found by running scripts/kernel-doc, which is caused by using 'make W=1'. fs/9p/fid.c:35: warning: Function parameter or member 'pfid' not described in 'v9fs_fid_add' fs/9p/fid.c:35: warning: Excess function parameter 'fid' description in 'v9fs_fid_add' fs/9p/fid.c:80: warning: Function parameter or member 'pfid' not described in 'v9fs_open_fid_add' fs/9p/fid.c:80: warning: Excess function parameter 'fid' description in 'v9fs_open_fid_add' Link: https://lkml.kernel.org/r/20220615012039.43479-1-yang.lee@linux.alibaba.com Reported-by: Abaci Robot Signed-off-by: Yang Li [Dominique: further adjust comment] Signed-off-by: Dominique Martinet

9p fid refcount: cleanup p9_fid_put calls

2022-07-02T09:52:21Z

Simplify p9_fid_put cleanup path in many 9p functions since the function is noop on null or error fids. Also make the *_add_fid() helpers "steal" the fid by nulling its pointer, so put after them will be noop. This should lead to no change of behaviour Link: https://lkml.kernel.org/r/20220612085330.1451496-7-asmadeus@codewreck.org Reviewed-by: Tyler Hicks Signed-off-by: Dominique Martinet

9p fid refcount: add p9_fid_get/put wrappers

2022-07-02T09:52:21Z

I was recently reminded that it is not clear that p9_client_clunk() was actually just decrementing refcount and clunking only when that reaches zero: make it clear through a set of helpers. This will also allow instrumenting refcounting better for debugging next patch Link: https://lkml.kernel.org/r/20220612085330.1451496-5-asmadeus@codewreck.org Reviewed-by: Tyler Hicks Reviewed-by: Christian Schoenebeck Signed-off-by: Dominique Martinet

9p: Fix minor typo in code comment

2022-07-02T09:52:21Z

Fix s/patch/path/ typo and make it clear that we're talking about multiple path components. Link: https://lkml.kernel.org/r/20220527000003.355812-6-tyhicks@linux.microsoft.com Signed-off-by: Tyler Hicks Signed-off-by: Dominique Martinet

9p: Remove unnecessary variable for old fids while walking from d_parent

2022-07-02T09:52:21Z

Remove the ofid variable that's local to the conditional block in favor of the old_fid variable that's local to the entire function. Link: https://lkml.kernel.org/r/20220527000003.355812-5-tyhicks@linux.microsoft.com Signed-off-by: Tyler Hicks Signed-off-by: Dominique Martinet

9p: Make the path walk logic more clear about when cloning is required

2022-07-02T09:52:21Z

Cloning during a path component walk is only needed when the old fid used for the walk operation is the root fid. Make that clear by comparing the two fids rather than using an additional variable. Link: https://lkml.kernel.org/r/20220527000003.355812-4-tyhicks@linux.microsoft.com Signed-off-by: Tyler Hicks Signed-off-by: Dominique Martinet

9p: Track the root fid with its own variable during lookups

2022-07-02T09:52:21Z

Improve readability by using a new variable when dealing with the root fid. The root fid requires special handling in comparison to other fids used during fid lookup. Link: https://lkml.kernel.org/r/20220527000003.355812-3-tyhicks@linux.microsoft.com Signed-off-by: Tyler Hicks Signed-off-by: Dominique Martinet

9p: fix EBADF errors in cached mode

2022-06-16T21:03:30Z

cached operations sometimes need to do invalid operations (e.g. read on a write only file) Historic fscache had added a "writeback fid", a special handle opened RW as root, for this. The conversion to new fscache missed that bit. This commit reinstates a slightly lesser variant of the original code that uses the writeback fid for partial pages backfills if the regular user fid had been open as WRONLY, and thus would lack read permissions. Link: https://lkml.kernel.org/r/20220614033802.1606738-1-asmadeus@codewreck.org Fixes: eb497943fa21 ("9p: Convert to using the netfs helper lib to do reads and caching") Cc: stable@vger.kernel.org Cc: David Howells Reported-By: Christian Schoenebeck Reviewed-by: Christian Schoenebeck Tested-by: Christian Schoenebeck Signed-off-by: Dominique Martinet

9p: Fix refcounting during full path walks for fid lookups

2022-06-15T03:05:33Z

Decrement the refcount of the parent dentry's fid after walking each path component during a full path walk for a lookup. Failure to do so can lead to fids that are not clunked until the filesystem is unmounted, as indicated by this warning: 9pnet: found fid 3 not clunked The improper refcounting after walking resulted in open(2) returning -EIO on any directories underneath the mount point when using the virtio transport. When using the fd transport, there's no apparent issue until the filesytem is unmounted and the warning above is emitted to the logs. In some cases, the user may not yet be attached to the filesystem and a new root fid, associated with the user, is created and attached to the root dentry before the full path walk is performed. Increment the new root fid's refcount to two in that situation so that it can be safely decremented to one after it is used for the walk operation. The new fid will still be attached to the root dentry when v9fs_fid_lookup_with_uid() returns so a final refcount of one is correct/expected. Link: https://lkml.kernel.org/r/20220527000003.355812-2-tyhicks@linux.microsoft.com Link: https://lkml.kernel.org/r/20220612085330.1451496-4-asmadeus@codewreck.org Fixes: 6636b6dcc3db ("9p: add refcount to p9_fid struct") Cc: stable@vger.kernel.org Signed-off-by: Tyler Hicks Reviewed-by: Christian Schoenebeck [Dominique: fix clunking fid multiple times discussed in second link] Signed-off-by: Dominique Martinet

9p: fix fid refcount leak in v9fs_vfs_get_link

2022-06-15T03:05:29Z

we check for protocol version later than required, after a fid has been obtained. Just move the version check earlier. Link: https://lkml.kernel.org/r/20220612085330.1451496-3-asmadeus@codewreck.org Fixes: 6636b6dcc3db ("9p: add refcount to p9_fid struct") Cc: stable@vger.kernel.org Reviewed-by: Tyler Hicks Reviewed-by: Christian Schoenebeck Signed-off-by: Dominique Martinet