Commit Graph

705 Commits

Author SHA1 Message Date
Linus Torvalds
e3b862ed89 9p-for-6.2-rc1
- improve p9_check_errors to check buffer size instead of msize when possible
 (e.g. not zero-copy)
 - some more syzbot and KCSAN fixes
 - minor headers include cleanup
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEE/IPbcYBuWt0zoYhOq06b7GqY5nAFAmOljPwACgkQq06b7GqY
 5nDRjw//aJU+tdcKCMije/ul4hMWDlvMwxn7x6p0ELdomefs+ykS/knBxXSVIoEs
 PrbVJVZVqOOOAn/IwWe8cMBD+hal0fLUErRbfrtzmOdkiF7z8PavJ209OeJLKBgD
 ffL+bq6FhcVC6jVXcwVHoZkX9bb4pnM7/lsJrO0UjBw+fT3ceqtK0vsTa+R2xEOj
 9lOS5124u69GVa9UvwQzqHko+UUx5T6XlULZYjNBEdtJqGULGi2oAABrae64R3N2
 auaj5LRKzAFOx4zkJ+crCH1h08uZ4bfTyCHpfCeTHwWb1duKD3u4jMq9PhdetF4E
 A6NYnOdeMxbV/sZfFOjjNWQrzP1TQJLmF6IVGSZkVQrlCjrZh7xQ5dr/AHrKr6be
 U+NXb0UCmAS6/Gs7Sxq5jnihDHzJ4rYG+oFdYdNrwPrrpQXsYmmRh+bm61m/t40T
 2JxBIiSt2KWL487AHsKisb6OsiH65N1ojntO5QJObZId4UdnhFJU6OaAzqv0Cojv
 mqKlZ0UPyxICXNCL227w+SdDFgK25efdLF1Z1547hS5DO0+43oWAtnvd3KrRpjZ6
 CmV9ARvdhHt49lNedbxmJAre5FusJQLeULuRzhMbd4mdcG7mKAmGTdM3u+AlFRIu
 Te1ZotTJXxs16Yn/whWRShAooUnK9FbXzC3kViiibziYZlCfK+s=
 =xLkl
 -----END PGP SIGNATURE-----

Merge tag '9p-for-6.2-rc1' of https://github.com/martinetd/linux

Pull 9p updates from Dominique Martinet:

 - improve p9_check_errors to check buffer size instead of msize when
   possible (e.g. not zero-copy)

 - some more syzbot and KCSAN fixes

 - minor headers include cleanup

* tag '9p-for-6.2-rc1' of https://github.com/martinetd/linux:
  9p/client: fix data race on req->status
  net/9p: fix response size check in p9_check_errors()
  net/9p: distinguish zero-copy requests
  9p/xen: do not memcpy header into req->rc
  9p: set req refcount to zero to avoid uninitialized usage
  9p/net: Remove unneeded idr.h #include
  9p/fs: Remove unneeded idr.h #include
2022-12-23 11:39:18 -08:00
Linus Torvalds
6a518afcc2 fs.acl.rework.v6.2
-----BEGIN PGP SIGNATURE-----
 
 iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCY5bwTgAKCRCRxhvAZXjc
 ovd2AQCK00NAtGjQCjQPQGyTa4GAPqvWgq1ef0lnhv+TL5US5gD9FncQ8UofeMXt
 pBfjtAD6ettTPCTxUQfnTwWEU4rc7Qg=
 =27Wm
 -----END PGP SIGNATURE-----

Merge tag 'fs.acl.rework.v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping

Pull VFS acl updates from Christian Brauner:
 "This contains the work that builds a dedicated vfs posix acl api.

  The origins of this work trace back to v5.19 but it took quite a while
  to understand the various filesystem specific implementations in
  sufficient detail and also come up with an acceptable solution.

  As we discussed and seen multiple times the current state of how posix
  acls are handled isn't nice and comes with a lot of problems: The
  current way of handling posix acls via the generic xattr api is error
  prone, hard to maintain, and type unsafe for the vfs until we call
  into the filesystem's dedicated get and set inode operations.

  It is already the case that posix acls are special-cased to death all
  the way through the vfs. There are an uncounted number of hacks that
  operate on the uapi posix acl struct instead of the dedicated vfs
  struct posix_acl. And the vfs must be involved in order to interpret
  and fixup posix acls before storing them to the backing store, caching
  them, reporting them to userspace, or for permission checking.

  Currently a range of hacks and duct tape exist to make this work. As
  with most things this is really no ones fault it's just something that
  happened over time. But the code is hard to understand and difficult
  to maintain and one is constantly at risk of introducing bugs and
  regressions when having to touch it.

  Instead of continuing to hack posix acls through the xattr handlers
  this series builds a dedicated posix acl api solely around the get and
  set inode operations.

  Going forward, the vfs_get_acl(), vfs_remove_acl(), and vfs_set_acl()
  helpers must be used in order to interact with posix acls. They
  operate directly on the vfs internal struct posix_acl instead of
  abusing the uapi posix acl struct as we currently do. In the end this
  removes all of the hackiness, makes the codepaths easier to maintain,
  and gets us type safety.

  This series passes the LTP and xfstests suites without any
  regressions. For xfstests the following combinations were tested:
   - xfs
   - ext4
   - btrfs
   - overlayfs
   - overlayfs on top of idmapped mounts
   - orangefs
   - (limited) cifs

  There's more simplifications for posix acls that we can make in the
  future if the basic api has made it.

  A few implementation details:

   - The series makes sure to retain exactly the same security and
     integrity module permission checks. Especially for the integrity
     modules this api is a win because right now they convert the uapi
     posix acl struct passed to them via a void pointer into the vfs
     struct posix_acl format to perform permission checking on the mode.

     There's a new dedicated security hook for setting posix acls which
     passes the vfs struct posix_acl not a void pointer. Basing checking
     on the posix acl stored in the uapi format is really unreliable.
     The vfs currently hacks around directly in the uapi struct storing
     values that frankly the security and integrity modules can't
     correctly interpret as evidenced by bugs we reported and fixed in
     this area. It's not necessarily even their fault it's just that the
     format we provide to them is sub optimal.

   - Some filesystems like 9p and cifs need access to the dentry in
     order to get and set posix acls which is why they either only
     partially or not even at all implement get and set inode
     operations. For example, cifs allows setxattr() and getxattr()
     operations but doesn't allow permission checking based on posix
     acls because it can't implement a get acl inode operation.

     Thus, this patch series updates the set acl inode operation to take
     a dentry instead of an inode argument. However, for the get acl
     inode operation we can't do this as the old get acl method is
     called in e.g., generic_permission() and inode_permission(). These
     helpers in turn are called in various filesystem's permission inode
     operation. So passing a dentry argument to the old get acl inode
     operation would amount to passing a dentry to the permission inode
     operation which we shouldn't and probably can't do.

     So instead of extending the existing inode operation Christoph
     suggested to add a new one. He also requested to ensure that the
     get and set acl inode operation taking a dentry are consistently
     named. So for this version the old get acl operation is renamed to
     ->get_inode_acl() and a new ->get_acl() inode operation taking a
     dentry is added. With this we can give both 9p and cifs get and set
     acl inode operations and in turn remove their complex custom posix
     xattr handlers.

     In the future I hope to get rid of the inode method duplication but
     it isn't like we have never had this situation. Readdir is just one
     example. And frankly, the overall gain in type safety and the more
     pleasant api wise are simply too big of a benefit to not accept
     this duplication for a while.

   - We've done a full audit of every codepaths using variant of the
     current generic xattr api to get and set posix acls and
     surprisingly it isn't that many places. There's of course always a
     chance that we might have missed some and if so I'm sure we'll find
     them soon enough.

     The crucial codepaths to be converted are obviously stacking
     filesystems such as ecryptfs and overlayfs.

     For a list of all callers currently using generic xattr api helpers
     see [2] including comments whether they support posix acls or not.

   - The old vfs generic posix acl infrastructure doesn't obey the
     create and replace semantics promised on the setxattr(2) manpage.
     This patch series doesn't address this. It really is something we
     should revisit later though.

  The patches are roughly organized as follows:

   (1) Change existing set acl inode operation to take a dentry
       argument (Intended to be a non-functional change)

   (2) Rename existing get acl method (Intended to be a non-functional
       change)

   (3) Implement get and set acl inode operations for filesystems that
       couldn't implement one before because of the missing dentry.
       That's mostly 9p and cifs (Intended to be a non-functional
       change)

   (4) Build posix acl api, i.e., add vfs_get_acl(), vfs_remove_acl(),
       and vfs_set_acl() including security and integrity hooks
       (Intended to be a non-functional change)

   (5) Implement get and set acl inode operations for stacking
       filesystems (Intended to be a non-functional change)

   (6) Switch posix acl handling in stacking filesystems to new posix
       acl api now that all filesystems it can stack upon support it.

   (7) Switch vfs to new posix acl api (semantical change)

   (8) Remove all now unused helpers

   (9) Additional regression fixes reported after we merged this into
       linux-next

  Thanks to Seth for a lot of good discussion around this and
  encouragement and input from Christoph"

* tag 'fs.acl.rework.v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping: (36 commits)
  posix_acl: Fix the type of sentinel in get_acl
  orangefs: fix mode handling
  ovl: call posix_acl_release() after error checking
  evm: remove dead code in evm_inode_set_acl()
  cifs: check whether acl is valid early
  acl: make vfs_posix_acl_to_xattr() static
  acl: remove a slew of now unused helpers
  9p: use stub posix acl handlers
  cifs: use stub posix acl handlers
  ovl: use stub posix acl handlers
  ecryptfs: use stub posix acl handlers
  evm: remove evm_xattr_acl_change()
  xattr: use posix acl api
  ovl: use posix acl api
  ovl: implement set acl method
  ovl: implement get acl method
  ecryptfs: implement set acl method
  ecryptfs: implement get acl method
  ksmbd: use vfs_remove_acl()
  acl: add vfs_remove_acl()
  ...
2022-12-12 18:46:39 -08:00
Christophe JAILLET
6e0149a553 9p/fs: Remove unneeded idr.h #include
The 9p fs does not use IDR or IDA functionalities. So there is no point in
including <linux/idr.h>.
Remove it.

Link: https://lkml.kernel.org/r/3d1e0ed9714eaee7e18d9f5b0b4bfa49b00b286d.1669553950.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
[Dominique: reword subject]
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-12-02 23:59:15 +09:00
Al Viro
de4eda9de2 use less confusing names for iov_iter direction initializers
READ/WRITE proved to be actively confusing - the meanings are
"data destination, as used with read(2)" and "data source, as
used with write(2)", but people keep interpreting those as
"we read data from it" and "we write data to it", i.e. exactly
the wrong way.

Call them ITER_DEST and ITER_SOURCE - at least that is harder
to misinterpret...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2022-11-25 13:01:55 -05:00
Christian Brauner
39a6497a9b
9p: use stub posix acl handlers
Now that 9p supports the get and set acl inode operations and the vfs
has been switched to the new posi api, 9p can simply rely on the stub
posix acl handlers. The custom xattr handlers and associated unused
helpers can be removed.

Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-10-20 10:13:32 +02:00
Christian Brauner
079da62938
9p: implement set acl method
The current way of setting and getting posix acls through the generic
xattr interface is error prone and type unsafe. The vfs needs to
interpret and fixup posix acls before storing or reporting it to
userspace. Various hacks exist to make this work. The code is hard to
understand and difficult to maintain in it's current form. Instead of
making this work by hacking posix acls through xattr handlers we are
building a dedicated posix acl api around the get and set inode
operations. This removes a lot of hackiness and makes the codepaths
easier to maintain. A lot of background can be found in [1].

In order to build a type safe posix api around get and set acl we need
all filesystem to implement get and set acl.

So far 9p implemented a ->get_inode_acl() operation that didn't require
access to the dentry in order to allow (limited) permission checking via
posix acls in the vfs. Now that we have get and set acl inode operations
that take a dentry argument we can give 9p get and set acl inode
operations.

This is mostly a light refactoring of the codepaths currently used in 9p
posix acl xattr handler. After we have fully implemented the posix acl
api and switched the vfs over to it, the 9p specific posix acl xattr
handler and associated code will be removed.

Note, until the vfs has been switched to the new posix acl api this
patch is a non-functional change.

Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1]
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-10-20 10:13:28 +02:00
Christian Brauner
6cd4d4e8b6
9p: implement get acl method
The current way of setting and getting posix acls through the generic
xattr interface is error prone and type unsafe. The vfs needs to
interpret and fixup posix acls before storing or reporting it to
userspace. Various hacks exist to make this work. The code is hard to
understand and difficult to maintain in it's current form. Instead of
making this work by hacking posix acls through xattr handlers we are
building a dedicated posix acl api around the get and set inode
operations. This removes a lot of hackiness and makes the codepaths
easier to maintain. A lot of background can be found in [1].

In order to build a type safe posix api around get and set acl we need
all filesystem to implement get and set acl.

So far 9p implemented a ->get_inode_acl() operation that didn't require
access to the dentry in order to allow (limited) permission checking via
posix acls in the vfs. Now that we have get and set acl inode operations
that take a dentry argument we can give 9p get and set acl inode
operations.

This is mostly a refactoring of the codepaths currently used in 9p posix
acl xattr handler. After we have fully implemented the posix acl api and
switched the vfs over to it, the 9p specific posix acl xattr handler and
associated code will be removed.

Note, until the vfs has been switched to the new posix acl api this
patch is a non-functional change.

Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1]
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-10-20 10:13:28 +02:00
Christian Brauner
cac2f8b8d8
fs: rename current get acl method
The current way of setting and getting posix acls through the generic
xattr interface is error prone and type unsafe. The vfs needs to
interpret and fixup posix acls before storing or reporting it to
userspace. Various hacks exist to make this work. The code is hard to
understand and difficult to maintain in it's current form. Instead of
making this work by hacking posix acls through xattr handlers we are
building a dedicated posix acl api around the get and set inode
operations. This removes a lot of hackiness and makes the codepaths
easier to maintain. A lot of background can be found in [1].

The current inode operation for getting posix acls takes an inode
argument but various filesystems (e.g., 9p, cifs, overlayfs) need access
to the dentry. In contrast to the ->set_acl() inode operation we cannot
simply extend ->get_acl() to take a dentry argument. The ->get_acl()
inode operation is called from:

acl_permission_check()
-> check_acl()
   -> get_acl()

which is part of generic_permission() which in turn is part of
inode_permission(). Both generic_permission() and inode_permission() are
called in the ->permission() handler of various filesystems (e.g.,
overlayfs). So simply passing a dentry argument to ->get_acl() would
amount to also having to pass a dentry argument to ->permission(). We
should avoid this unnecessary change.

So instead of extending the existing inode operation rename it from
->get_acl() to ->get_inode_acl() and add a ->get_acl() method later that
passes a dentry argument and which filesystems that need access to the
dentry can implement instead of ->get_inode_acl(). Filesystems like cifs
which allow setting and getting posix acls but not using them for
permission checking during lookup can simply not implement
->get_inode_acl().

This is intended to be a non-functional change.

Link: https://lore.kernel.org/all/20220801145520.1532837-1-brauner@kernel.org [1]
Suggested-by/Inspired-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2022-10-20 10:13:27 +02:00
Yang Li
e3baced02a 9p: Fix some kernel-doc comments
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 <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
[Dominique: further adjust comment]
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-07-02 18:52:21 +09:00
Dominique Martinet
dafbe68973 9p fid refcount: cleanup p9_fid_put calls
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 <tyhicks@linux.microsoft.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-07-02 18:52:21 +09:00
Dominique Martinet
b48dbb998d 9p fid refcount: add p9_fid_get/put wrappers
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 <tyhicks@linux.microsoft.com>
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-07-02 18:52:21 +09:00
Tyler Hicks
b296d05746 9p: Fix minor typo in code comment
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 <tyhicks@linux.microsoft.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-07-02 18:52:21 +09:00
Tyler Hicks
47b1e3432b 9p: Remove unnecessary variable for old fids while walking from d_parent
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 <tyhicks@linux.microsoft.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-07-02 18:52:21 +09:00
Tyler Hicks
c58c72d301 9p: Make the path walk logic more clear about when cloning is required
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 <tyhicks@linux.microsoft.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-07-02 18:52:21 +09:00
Tyler Hicks
cba83f47fc 9p: Track the root fid with its own variable during lookups
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 <tyhicks@linux.microsoft.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-07-02 18:52:21 +09:00
Dominique Martinet
b0017602fd 9p: fix EBADF errors in cached mode
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: eb497943fa ("9p: Convert to using the netfs helper lib to do reads and caching")
Cc: stable@vger.kernel.org
Cc: David Howells <dhowells@redhat.com>
Reported-By: Christian Schoenebeck <linux_oss@crudebyte.com>
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
Tested-by: Christian Schoenebeck <linux_oss@crudebyte.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-06-17 06:03:30 +09:00
Tyler Hicks
2a3dcbccd6 9p: Fix refcounting during full path walks for fid lookups
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: 6636b6dcc3 ("9p: add refcount to p9_fid struct")
Cc: stable@vger.kernel.org
Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
[Dominique: fix clunking fid multiple times discussed in second link]
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-06-15 12:05:33 +09:00
Dominique Martinet
e5690f2632 9p: fix fid refcount leak in v9fs_vfs_get_link
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: 6636b6dcc3 ("9p: add refcount to p9_fid struct")
Cc: stable@vger.kernel.org
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-06-15 12:05:29 +09:00
Dominique Martinet
beca774fc5 9p: fix fid refcount leak in v9fs_vfs_atomic_open_dotl
We need to release directory fid if we fail halfway through open

This fixes fid leaking with xfstests generic 531

Link: https://lkml.kernel.org/r/20220612085330.1451496-2-asmadeus@codewreck.org
Fixes: 6636b6dcc3 ("9p: add refcount to p9_fid struct")
Cc: stable@vger.kernel.org
Reported-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>
Reviewed-by: Christian Schoenebeck <linux_oss@crudebyte.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-06-15 12:05:21 +09:00
David Howells
40a8110120 netfs: Rename the netfs_io_request cleanup op and give it an op pointer
The netfs_io_request cleanup op is now always in a position to be given a
pointer to a netfs_io_request struct, so this can be passed in instead of
the mapping and private data arguments (both of which are included in the
struct).

So rename the ->cleanup op to ->free_request (to match ->init_request) and
pass in the I/O pointer.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
2022-06-10 20:55:21 +01:00
Linus Torvalds
e81fb4198e netfs: Further cleanups after struct netfs_inode wrapper introduced
Change the signature of netfs helper functions to take a struct netfs_inode
pointer rather than a struct inode pointer where appropriate, thereby
relieving the need for the network filesystem to convert its internal inode
format down to the VFS inode only for netfslib to bounce it back up.  For
type safety, it's better not to do that (and it's less typing too).

Give netfs_write_begin() an extra argument to pass in a pointer to the
netfs_inode struct rather than deriving it internally from the file
pointer.  Note that the ->write_begin() and ->write_end() ops are intended
to be replaced in the future by netfslib code that manages this without the
need to call in twice for each page.

netfs_readpage() and similar are intended to be pointed at directly by the
address_space_operations table, so must stick to the signature dictated by
the function pointers there.

Changes
=======
- Updated the kerneldoc comments and documentation [DH].

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/CAHk-=wgkwKyNmNdKpQkqZ6DnmUL-x9hp0YBnUGjaPFEAdxDTbw@mail.gmail.com/
2022-06-10 20:55:21 +01:00
David Howells
874c8ca1e6 netfs: Fix gcc-12 warning by embedding vfs inode in netfs_i_context
While randstruct was satisfied with using an open-coded "void *" offset
cast for the netfs_i_context <-> inode casting, __builtin_object_size() as
used by FORTIFY_SOURCE was not as easily fooled.  This was causing the
following complaint[1] from gcc v12:

  In file included from include/linux/string.h:253,
                   from include/linux/ceph/ceph_debug.h:7,
                   from fs/ceph/inode.c:2:
  In function 'fortify_memset_chk',
      inlined from 'netfs_i_context_init' at include/linux/netfs.h:326:2,
      inlined from 'ceph_alloc_inode' at fs/ceph/inode.c:463:2:
  include/linux/fortify-string.h:242:25: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning]
    242 |                         __write_overflow_field(p_size_field, size);
        |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fix this by embedding a struct inode into struct netfs_i_context (which
should perhaps be renamed to struct netfs_inode).  The struct inode
vfs_inode fields are then removed from the 9p, afs, ceph and cifs inode
structs and vfs_inode is then simply changed to "netfs.inode" in those
filesystems.

Further, rename netfs_i_context to netfs_inode, get rid of the
netfs_inode() function that converted a netfs_i_context pointer to an
inode pointer (that can now be done with &ctx->inode) and rename the
netfs_i_context() function to netfs_inode() (which is now a wrapper
around container_of()).

Most of the changes were done with:

  perl -p -i -e 's/vfs_inode/netfs.inode/'g \
        `git grep -l 'vfs_inode' -- fs/{9p,afs,ceph,cifs}/*.[ch]`

Kees suggested doing it with a pair structure[2] and a special
declarator to insert that into the network filesystem's inode
wrapper[3], but I think it's cleaner to embed it - and then it doesn't
matter if struct randomisation reorders things.

Dave Chinner suggested using a filesystem-specific VFS_I() function in
each filesystem to convert that filesystem's own inode wrapper struct
into the VFS inode struct[4].

Version #2:
 - Fix a couple of missed name changes due to a disabled cifs option.
 - Rename nfs_i_context to nfs_inode
 - Use "netfs" instead of "nic" as the member name in per-fs inode wrapper
   structs.

[ This also undoes commit 507160f46c ("netfs: gcc-12: temporarily
  disable '-Wattribute-warning' for now") that is no longer needed ]

Fixes: bc899ee1c8 ("netfs: Add a netfs inode context")
Reported-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Xiubo Li <xiubli@redhat.com>
cc: Jonathan Corbet <corbet@lwn.net>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Christian Schoenebeck <linux_oss@crudebyte.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Steve French <smfrench@gmail.com>
cc: William Kucharski <william.kucharski@oracle.com>
cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
cc: Dave Chinner <david@fromorbit.com>
cc: linux-doc@vger.kernel.org
cc: v9fs-developer@lists.sourceforge.net
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: samba-technical@lists.samba.org
cc: linux-fsdevel@vger.kernel.org
cc: linux-hardening@vger.kernel.org
Link: https://lore.kernel.org/r/d2ad3a3d7bdd794c6efb562d2f2b655fb67756b9.camel@kernel.org/ [1]
Link: https://lore.kernel.org/r/20220517210230.864239-1-keescook@chromium.org/ [2]
Link: https://lore.kernel.org/r/20220518202212.2322058-1-keescook@chromium.org/ [3]
Link: https://lore.kernel.org/r/20220524101205.GI2306852@dread.disaster.area/ [4]
Link: https://lore.kernel.org/r/165296786831.3591209.12111293034669289733.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/165305805651.4094995.7763502506786714216.stgit@warthog.procyon.org.uk # v2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-06-09 13:55:00 -07:00
Matthew Wilcox (Oracle)
a26d3411bb 9p: Convert to release_folio
A straightforward conversion as it already works in terms of folios.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
2022-05-09 23:12:32 -04:00
Matthew Wilcox (Oracle)
6c62371b7f fs: Convert netfs_readpage to netfs_read_folio
This is straightforward because netfs already worked in terms of folios.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
2022-05-09 16:21:44 -04:00
Matthew Wilcox (Oracle)
9d6b0cd757 fs: Remove flags parameter from aops->write_begin
There are no more aop flags left, so remove the parameter.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2022-05-08 14:28:19 -04:00
Matthew Wilcox (Oracle)
de2a931150 fs: Remove aop_flags parameter from netfs_write_begin()
There are no more aop flags left, so remove the parameter.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2022-05-08 14:28:19 -04:00
Linus Torvalds
f008b1d6e1 Netfs prep for write helpers
-----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEEqG5UsNXhtOCrfGQP+7dXa6fLC2sFAmI1HOwACgkQ+7dXa6fL
 C2u9mA/+LUdXHqlvET/PAtFTg75bUPeOFGLnuDnYl1Ng2FCKMSodAohpbVtENxsK
 E/gTVS7uiVZFQgC+YmNA00z6eIQkAaDVyvKyEcUbKREBbUgONfJ/HLeaK/NvVKxx
 TY5gx/POdG6yHRQXL6JGBqSJUB8bZrGKwnJm8ebzeKOji9n7GSJBYiMlYBA7EAhs
 Aut/P7Y39ISHLw3y+y5czBeRoubljmTyznbP20xUZEzrRwhTpNwpJVzBGUZU635T
 93Sqcp//0U5LIdn6Pg6DUGHBMBTNDNJChb21ZoBusF/HHswXsOOnf/mcRUBSJUTI
 M1WSpNLk8PRBgajMdIymQpGU1sCZZzJ3krrSA3RcXdN6GPHwZg8kKjoroHsLDL6l
 igPbDSMJ5wfiwA2A2gXbY1CkAl3ik5ccb7ZqhTwS0WBk0vOnHmAsE9cs/bBo7Xii
 GTiWXEFOgtJiXANPMS2P9DiOS3ZQNf+wxotCYdkGPOXuX9wnIo1Kmy8XfujQ1bXf
 pJsEZKfeyROKrzyKWgqLI64/Kg5xNueoFQZfDpOlZYzF1uDstynADPUt0eQD706q
 jcuKaXLN3rn5gSPun5mWOYbRtXVgOLdFL/7zptMVJwFKBFguQENhjG4UMNZcjkVA
 3Mr0kGocsgoCSk1oDBkFlrw1wIsXxWbkRBL1Pww6kovivuGUwoo=
 =j0yx
 -----END PGP SIGNATURE-----

Merge tag 'netfs-prep-20220318' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs

Pull netfs updates from David Howells:
 "Netfs prep for write helpers.

  Having had a go at implementing write helpers and content encryption
  support in netfslib, it seems that the netfs_read_{,sub}request
  structs and the equivalent write request structs were almost the same
  and so should be merged, thereby requiring only one set of
  alloc/get/put functions and a common set of tracepoints.

  Merging the structs also has the advantage that if a bounce buffer is
  added to the request struct, a read operation can be performed to fill
  the bounce buffer, the contents of the buffer can be modified and then
  a write operation can be performed on it to send the data wherever it
  needs to go using the same request structure all the way through. The
  I/O handlers would then transparently perform any required crypto.
  This should make it easier to perform RMW cycles if needed.

  The potentially common functions and structs, however, by their names
  all proclaim themselves to be associated with the read side of things.

  The bulk of these changes alter this in the following ways:

   - Rename struct netfs_read_{,sub}request to netfs_io_{,sub}request.

   - Rename some enums, members and flags to make them more appropriate.

   - Adjust some comments to match.

   - Drop "read"/"rreq" from the names of common functions. For
     instance, netfs_get_read_request() becomes netfs_get_request().

   - The ->init_rreq() and ->issue_op() methods become ->init_request()
     and ->issue_read(). I've kept the latter as a read-specific
     function and in another branch added an ->issue_write() method.

  The driver source is then reorganised into a number of files:

        fs/netfs/buffered_read.c        Create read reqs to the pagecache
        fs/netfs/io.c                   Dispatchers for read and write reqs
        fs/netfs/main.c                 Some general miscellaneous bits
        fs/netfs/objects.c              Alloc, get and put functions
        fs/netfs/stats.c                Optional procfs statistics.

  and future development can be fitted into this scheme, e.g.:

        fs/netfs/buffered_write.c       Modify the pagecache
        fs/netfs/buffered_flush.c       Writeback from the pagecache
        fs/netfs/direct_read.c          DIO read support
        fs/netfs/direct_write.c         DIO write support
        fs/netfs/unbuffered_write.c     Write modifications directly back

  Beyond the above changes, there are also some changes that affect how
  things work:

   - Make fscache_end_operation() generally available.

   - In the netfs tracing header, generate enums from the symbol ->
     string mapping tables rather than manually coding them.

   - Add a struct for filesystems that uses netfslib to put into their
     inode wrapper structs to hold extra state that netfslib is
     interested in, such as the fscache cookie. This allows netfslib
     functions to be set in filesystem operation tables and jumped to
     directly without having to have a filesystem wrapper.

   - Add a member to the struct added above to track the remote inode
     length as that may differ if local modifications are buffered. We
     may need to supply an appropriate EOF pointer when storing data (in
     AFS for example).

   - Pass extra information to netfs_alloc_request() so that the
     ->init_request() hook can access it and retain information to
     indicate the origin of the operation.

   - Make the ->init_request() hook return an error, thereby allowing a
     filesystem that isn't allowed to cache an inode (ceph or cifs, for
     example) to skip readahead.

   - Switch to using refcount_t for subrequests and add tracepoints to
     log refcount changes for the request and subrequest structs.

   - Add a function to consolidate dispatching a read request. Similar
     code is used in three places and another couple are likely to be
     added in the future"

Link: https://lore.kernel.org/all/2639515.1648483225@warthog.procyon.org.uk/

* tag 'netfs-prep-20220318' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: Maintain netfs_i_context::remote_i_size
  netfs: Keep track of the actual remote file size
  netfs: Split some core bits out into their own file
  netfs: Split fs/netfs/read_helper.c
  netfs: Rename read_helper.c to io.c
  netfs: Prepare to split read_helper.c
  netfs: Add a function to consolidate beginning a read
  netfs: Add a netfs inode context
  ceph: Make ceph_init_request() check caps on readahead
  netfs: Change ->init_request() to return an error code
  netfs: Refactor arguments for netfs_alloc_read_request
  netfs: Adjust the netfs_failure tracepoint to indicate non-subreq lines
  netfs: Trace refcounting on the netfs_io_subrequest struct
  netfs: Trace refcounting on the netfs_io_request struct
  netfs: Adjust the netfs_rreq tracepoint slightly
  netfs: Split netfs_io_* object handling out
  netfs: Finish off rename of netfs_read_request to netfs_io_request
  netfs: Rename netfs_read_*request to netfs_io_*request
  netfs: Generate enums from trace symbol mapping lists
  fscache: export fscache_end_operation()
2022-03-31 15:49:36 -07:00
Linus Torvalds
6b1f86f8e9 Filesystem folio changes for 5.18
Primarily this series converts some of the address_space operations
 to take a folio instead of a page.
 
 ->is_partially_uptodate() takes a folio instead of a page and changes the
 type of the 'from' and 'count' arguments to make it obvious they're bytes.
 ->invalidatepage() becomes ->invalidate_folio() and has a similar type change.
 ->launder_page() becomes ->launder_folio()
 ->set_page_dirty() becomes ->dirty_folio() and adds the address_space as
 an argument.
 
 There are a couple of other misc changes up front that weren't worth
 separating into their own pull request.
 -----BEGIN PGP SIGNATURE-----
 
 iQEzBAABCgAdFiEEejHryeLBw/spnjHrDpNsjXcpgj4FAmI4hqMACgkQDpNsjXcp
 gj7r7Af/fVJ7m8kKqjP/IayX3HiJRuIDQw+vM++BlRNXdjz+IyED6whdmFGxJeOY
 BMyT+8ApOAz7ErS4G+7fAv4ScJK/aEgFUsnSeAiCp0PliiEJ5NNJzElp6sVmQ7H5
 SX7+Ek444FZUGsQuy0qL7/ELpR3ditnD7x+5U2g0p5TeaHGUQn84crRyfR4xuhNG
 EBD9D71BOb7OxUcOHe93pTkK51QsQ0aCrcIsB1tkK5KR0BAthn1HqF7ehL90Rvrr
 omx5M7aDWGY4oj7IKrhlAs+55Ah2WaOzrZBp0FXNbr4UENDBKWKyUxErwa4xPkf6
 Gm1iQG/CspOHnxN3YWsd5WjtlL3A+A==
 =cOiq
 -----END PGP SIGNATURE-----

Merge tag 'folio-5.18b' of git://git.infradead.org/users/willy/pagecache

Pull filesystem folio updates from Matthew Wilcox:
 "Primarily this series converts some of the address_space operations to
  take a folio instead of a page.

  Notably:

   - a_ops->is_partially_uptodate() takes a folio instead of a page and
     changes the type of the 'from' and 'count' arguments to make it
     obvious they're bytes.

   - a_ops->invalidatepage() becomes ->invalidate_folio() and has a
     similar type change.

   - a_ops->launder_page() becomes ->launder_folio()

   - a_ops->set_page_dirty() becomes ->dirty_folio() and adds the
     address_space as an argument.

  There are a couple of other misc changes up front that weren't worth
  separating into their own pull request"

* tag 'folio-5.18b' of git://git.infradead.org/users/willy/pagecache: (53 commits)
  fs: Remove aops ->set_page_dirty
  fb_defio: Use noop_dirty_folio()
  fs: Convert __set_page_dirty_no_writeback to noop_dirty_folio
  fs: Convert __set_page_dirty_buffers to block_dirty_folio
  nilfs: Convert nilfs_set_page_dirty() to nilfs_dirty_folio()
  mm: Convert swap_set_page_dirty() to swap_dirty_folio()
  ubifs: Convert ubifs_set_page_dirty to ubifs_dirty_folio
  f2fs: Convert f2fs_set_node_page_dirty to f2fs_dirty_node_folio
  f2fs: Convert f2fs_set_data_page_dirty to f2fs_dirty_data_folio
  f2fs: Convert f2fs_set_meta_page_dirty to f2fs_dirty_meta_folio
  afs: Convert afs_dir_set_page_dirty() to afs_dir_dirty_folio()
  btrfs: Convert extent_range_redirty_for_io() to use folios
  fs: Convert trivial uses of __set_page_dirty_nobuffers to filemap_dirty_folio
  btrfs: Convert from set_page_dirty to dirty_folio
  fscache: Convert fscache_set_page_dirty() to fscache_dirty_folio()
  fs: Add aops->dirty_folio
  fs: Remove aops->launder_page
  orangefs: Convert launder_page to launder_folio
  nfs: Convert from launder_page to launder_folio
  fuse: Convert from launder_page to launder_folio
  ...
2022-03-22 18:26:56 -07:00
Muchun Song
fd60b28842 fs: allocate inode by using alloc_inode_sb()
The inode allocation is supposed to use alloc_inode_sb(), so convert
kmem_cache_alloc() of all filesystems to alloc_inode_sb().

Link: https://lkml.kernel.org/r/20220228122126.37293-5-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Theodore Ts'o <tytso@mit.edu>		[ext4]
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Alex Shi <alexs@kernel.org>
Cc: Anna Schumaker <Anna.Schumaker@Netapp.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Fam Zheng <fam.zheng@bytedance.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kari Argillander <kari.argillander@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Xiongchun Duan <duanxiongchun@bytedance.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-03-22 15:57:03 -07:00
David Howells
bc899ee1c8 netfs: Add a netfs inode context
Add a netfs_i_context struct that should be included in the network
filesystem's own inode struct wrapper, directly after the VFS's inode
struct, e.g.:

	struct my_inode {
		struct {
			/* These must be contiguous */
			struct inode		vfs_inode;
			struct netfs_i_context	netfs_ctx;
		};
	};

The netfs_i_context struct so far contains a single field for the network
filesystem to use - the cache cookie:

	struct netfs_i_context {
		...
		struct fscache_cookie	*cache;
	};

Three functions are provided to help with this:

 (1) void netfs_i_context_init(struct inode *inode,
			       const struct netfs_request_ops *ops);

     Initialise the netfs context and set the operations.

 (2) struct netfs_i_context *netfs_i_context(struct inode *inode);

     Find the netfs context from the VFS inode.

 (3) struct inode *netfs_inode(struct netfs_i_context *ctx);

     Find the VFS inode from the netfs context.

Changes
=======
ver #4)
 - Fix netfs_is_cache_enabled() to check cookie->cache_priv to see if a
   cache is present[3].
 - Fix netfs_skip_folio_read() to zero out all of the page, not just some
   of it[3].

ver #3)
 - Split out the bit to move ceph cap-getting on readahead into
   ceph_init_request()[1].
 - Stick in a comment to the netfs inode structs indicating the contiguity
   requirements[2].

ver #2)
 - Adjust documentation to match.
 - Use "#if IS_ENABLED()" in netfs_i_cookie(), not "#ifdef".
 - Move the cap check from ceph_readahead() to ceph_init_request() to be
   called from netfslib.
 - Remove ceph_readahead() and use  netfs_readahead() directly instead.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com

Link: https://lore.kernel.org/r/8af0d47f17d89c06bbf602496dd845f2b0bf25b3.camel@kernel.org/ [1]
Link: https://lore.kernel.org/r/beaf4f6a6c2575ed489adb14b257253c868f9a5c.camel@kernel.org/ [2]
Link: https://lore.kernel.org/r/3536452.1647421585@warthog.procyon.org.uk/ [3]
Link: https://lore.kernel.org/r/164622984545.3564931.15691742939278418580.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/164678213320.1200972.16807551936267647470.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/164692909854.2099075.9535537286264248057.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/306388.1647595110@warthog.procyon.org.uk/ # v4
2022-03-18 09:29:05 +00:00
David Howells
2de1604173 netfs: Change ->init_request() to return an error code
Change the request initialisation function to return an error code so that
the network filesystem can return a failure (ENOMEM, for example).

This will also allow ceph to abort a ->readahead() op if the server refuses
to give it a cap allowing local caching from within the netfslib framework
(errors aren't passed back through ->readahead(), so returning, say,
-ENOBUFS will cause the op to be aborted).

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com

Link: https://lore.kernel.org/r/164678212401.1200972.16537041523832944934.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/164692905398.2099075.5238033621684646524.stgit@warthog.procyon.org.uk/ # v3
2022-03-18 09:24:00 +00:00
David Howells
f18a378580 netfs: Finish off rename of netfs_read_request to netfs_io_request
Adjust helper function names and comments after mass rename of
struct netfs_read_*request to struct netfs_io_*request.

Changes
=======
ver #2)
 - Make the changes in the docs also.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com

Link: https://lore.kernel.org/r/164622992433.3564931.6684311087845150271.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/164678196111.1200972.5001114956865989528.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/164692892567.2099075.13895804222087028813.stgit@warthog.procyon.org.uk/ # v3
2022-03-18 09:24:00 +00:00
David Howells
6a19114b8e netfs: Rename netfs_read_*request to netfs_io_*request
Rename netfs_read_*request to netfs_io_*request so that the same structures
can be used for the write helpers too.

perl -p -i -e 's/netfs_read_(request|subrequest)/netfs_io_$1/g' \
   `git grep -l 'netfs_read_\(sub\|\)request'`
perl -p -i -e 's/nr_rd_ops/nr_outstanding/g' \
   `git grep -l nr_rd_ops`
perl -p -i -e 's/nr_wr_ops/nr_copy_ops/g' \
   `git grep -l nr_wr_ops`
perl -p -i -e 's/netfs_read_source/netfs_io_source/g' \
   `git grep -l 'netfs_read_source'`
perl -p -i -e 's/netfs_io_request_ops/netfs_request_ops/g' \
   `git grep -l 'netfs_io_request_ops'`
perl -p -i -e 's/init_rreq/init_request/g' \
   `git grep -l 'init_rreq'`

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com

Link: https://lore.kernel.org/r/164622988070.3564931.7089670190434315183.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/164678195157.1200972.366609966927368090.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/164692891535.2099075.18435198075367420588.stgit@warthog.procyon.org.uk/ # v3
2022-03-18 09:24:00 +00:00
Matthew Wilcox (Oracle)
8fb72b4a76 fscache: Convert fscache_set_page_dirty() to fscache_dirty_folio()
Convert all users of fscache_set_page_dirty to use fscache_dirty_folio.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Tested-by: Mike Marshall <hubcap@omnibond.com> # orangefs
Tested-by: David Howells <dhowells@redhat.com> # afs
2022-03-15 08:34:36 -04:00
Matthew Wilcox (Oracle)
76dba92720 9p: Convert from launder_page to launder_folio
Trivial conversion.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Tested-by: Mike Marshall <hubcap@omnibond.com> # orangefs
Tested-by: David Howells <dhowells@redhat.com> # afs
2022-03-15 08:23:30 -04:00
Matthew Wilcox (Oracle)
040cdd4bf9 9p: Convert to invalidate_folio
This is a trivial conversion.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Tested-by: Mike Marshall <hubcap@omnibond.com> # orangefs
Tested-by: David Howells <dhowells@redhat.com> # afs
2022-03-15 08:23:29 -04:00
Dominique Martinet
22e424feb6 Revert "fs/9p: search open fids first"
This reverts commit 478ba09edc.

That commit was meant as a fix for setattrs with by fd (e.g. ftruncate)
to use an open fid instead of the first fid it found on lookup.
The proper fix for that is to use the fid associated with the open file
struct, available in iattr->ia_file for such operations, and was
actually done just before in 6624664160 ("9p: retrieve fid from file
when file instance exist.")
As such, this commit is no longer required.

Furthermore, changing lookup to return open fids first had unwanted side
effects, as it turns out the protocol forbids the use of open fids for
further walks (e.g. clone_fid) and we broke mounts for some servers
enforcing this rule.

Note this only reverts to the old working behaviour, but it's still
possible for lookup to return open fids if dentry->d_fsdata is not set,
so more work is needed to make sure we respect this rule in the future,
for example by adding a flag to the lookup functions to only match
certain fid open modes depending on caller requirements.

Link: https://lkml.kernel.org/r/20220130130651.712293-1-asmadeus@codewreck.org
Fixes: 478ba09edc ("fs/9p: search open fids first")
Cc: stable@vger.kernel.org # v5.11+
Reported-by: ron minnich <rminnich@gmail.com>
Reported-by: ng@0x80.stream
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-01-30 22:13:37 +09:00
Linus Torvalds
49ad227d54 9p-for-5.17-rc1: fixes, split 9p_net_fd, new reviewer
- fix possible uninitialized memory usage for setattr
 - fix fscache reading hole in a file just after it's been grown
 - split net/9p/trans_fd.c in its own module like other transports
   that module defaults to 9P_NET and is autoloaded if required so
   users should not be impacted
 - add Christian Schoenebeck to 9p reviewers
 - some more trivial cleanup
 -----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEE/IPbcYBuWt0zoYhOq06b7GqY5nAFAmHgt18ACgkQq06b7GqY
 5nAdUA//ZHFTIcnbTiVkqbw0YztxedTOhdGCWcYsszux0pNQ/ZCjbP5NxESWiFxs
 raYWcvE98Xvq4fbs8b+m7YKBJzWF+Km/v1MKfgvZZWFLZR3MfWiL8iojlsaUgG9U
 rBmEUyaTWw2COIvFN7EqnwT5mwzNCli5d3AzaAmgffWsHEi/+EVU35YX70ySUkjW
 nVf08oX3dBB425oArXOZApOZSVRsUr5YDSuQGiFHBL+hvPTrvPumu/AXbjLbTbmf
 NuUxu1Akw8/jhWNATLHzjCdzJzBSfF0zRs+oH9Qt8MKkUrlTfjxc/2MbQYL1p1IN
 84XxiG02ebw+Mx05cydP9/Ll7gOo2p6ORGXMHcoPIAMy6zFiCKo3TRdKDgmYDauC
 K8c3v+osNwl2GFn1+2XoQIWnqXb7bJ1debkFtWVEGOPd/Yr6CYCZyfiZamoPJXUO
 TjkoLAJXJGKlV66ZCuVeAsySdUxdtwbj2WxTliDUWtxvQ+m1jt06S3f/TbA7a9bB
 8aBhx7FKzQ/UL8zhm4+3WLPlWkoSUXhFSZZUknvhuaHFV/S1xglXox5OAQJrJMy+
 qOzmOjCg14T1TC2WkJlEsedLUH8ACU+XueAPT6uqSdA4rvQEVzk32zTm/GfFu3Q3
 0RhcGlW5kAAYBTBLXvmKsjyW2OmPCSycgbWCu3E8A/1gubbRE40=
 =o2Lc
 -----END PGP SIGNATURE-----

Merge tag '9p-for-5.17-rc1' of git://github.com/martinetd/linux

Pull 9p updates from Dominique Martinet:
 "Fixes, split 9p_net_fd, and new reviewer:

   - fix possible uninitialized memory usage for setattr

   - fix fscache reading hole in a file just after it's been grown

   - split net/9p/trans_fd.c in its own module like other transports.

     The new transport module defaults to 9P_NET and is autoloaded if
     required so users should not be impacted

   - add Christian Schoenebeck to 9p reviewers

   - some more trivial cleanup"

* tag '9p-for-5.17-rc1' of git://github.com/martinetd/linux:
  9p: fix enodata when reading growing file
  net/9p: show error message if user 'msize' cannot be satisfied
  MAINTAINERS: 9p: add Christian Schoenebeck as reviewer
  9p: only copy valid iattrs in 9P2000.L setattr implementation
  9p: Use BUG_ON instead of if condition followed by BUG.
  net/p9: load default transports
  9p/xen: autoload when xenbus service is available
  9p/trans_fd: split into dedicated module
  fs: 9p: remove unneeded variable
  9p/trans_virtio: Fix typo in the comment for p9_virtio_create()
2022-01-16 07:36:49 +02:00
David Howells
d7bdba1c81 9p, afs, ceph, nfs: Use current_is_kswapd() rather than gfpflags_allow_blocking()
In 9p, afs ceph, and nfs, gfpflags_allow_blocking() (which wraps a
test for __GFP_DIRECT_RECLAIM being set) is used to determine if
->releasepage() should wait for the completion of a DIO write to fscache
with something like:

	if (folio_test_fscache(folio)) {
		if (!gfpflags_allow_blocking(gfp) || !(gfp & __GFP_FS))
			return false;
		folio_wait_fscache(folio);
	}

Instead, current_is_kswapd() should be used instead.

Note that this is based on a patch originally by Zhaoyang Huang[1].  In
addition to extending it to the other network filesystems and putting it on
top of my fscache rewrite, it also needs to include linux/swap.h in a bunch
of places.  Can current_is_kswapd() be moved to linux/mm.h?

Changes
=======
ver #5:
 - Dropping the changes for cifs.

Originally-signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
Co-developed-by: David Howells <dhowells@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Steve French <smfrench@gmail.com>
cc: Trond Myklebust <trond.myklebust@hammerspace.com>
cc: linux-cachefs@redhat.com
cc: v9fs-developer@lists.sourceforge.net
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: linux-nfs@vger.kernel.org
cc: linux-mm@kvack.org
Link: https://lore.kernel.org/r/1638952658-20285-1-git-send-email-huangzhaoyang@gmail.com/ [1]
Link: https://lore.kernel.org/r/164021590773.640689.16777975200823659231.stgit@warthog.procyon.org.uk/ # v4
2022-01-11 22:27:42 +00:00
Dominique Martinet
19d1c32652 9p: fix enodata when reading growing file
Reading from a file that was just extended by a write, but the write had
not yet reached the server would return ENODATA as illustrated by this
command:
$ xfs_io -c 'open -ft test' -c 'w 4096 1000' -c 'r 0 1000'
wrote 1000/1000 bytes at offset 4096
1000.000000 bytes, 1 ops; 0.0001 sec (5.610 MiB/sec and 5882.3529 ops/sec)
pread: No data available

Fix this case by having netfs assume zeroes when reads from server come
short like AFS and CEPH do

Link: https://lkml.kernel.org/r/20220110111444.926753-1-asmadeus@codewreck.org
Cc: stable@vger.kernel.org
Fixes: eb497943fa ("9p: Convert to using the netfs helper lib to do reads and caching")
Co-authored-by: David Howells <dhowells@redhat.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Tested-by: David Howells <dhowells@redhat.com>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-01-11 15:21:53 +09:00
David Howells
93c846143d 9p: Copy local writes to the cache when writing to the server
When writing to the server from v9fs_vfs_writepage(), copy the data to the
cache object too.

To make this possible, the cookie must have its active users count
incremented when the page is dirtied and kept incremented until we manage
to clean up all the pages.  This allows the writeback to take place after
the last file struct is released.

This is done by taking a use on the cookie in v9fs_set_page_dirty() if we
haven't already done so (controlled by the I_PINNING_FSCACHE_WB flag) and
dropping the pin in v9fs_write_inode() if __writeback_single_inode() clears
all the outstanding dirty pages (conveyed by the unpinned_fscache_wb flag
in the writeback_control struct).

Inode eviction must also clear the flag after truncating away all the
outstanding pages.

In the future this will be handled more gracefully by netfslib.

Changes
=======
ver #3:
 - Canonicalise the coherency data to make it endianness-independent.

ver #2:
 - Fix an unused-var warning due to CONFIG_9P_FSCACHE=n[1].

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Dominique Martinet <asmadeus@codewreck.org>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: v9fs-developer@lists.sourceforge.net
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819667027.215744.13815687931204222995.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906978015.143852.10646669694345706328.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967180760.1823006.5831751873616248910.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021574522.640689.13849966660182529125.stgit@warthog.procyon.org.uk/ # v4
2022-01-10 11:53:25 +00:00
David Howells
24e42e32d3 9p: Use fscache indexing rewrite and reenable caching
Change the 9p filesystem to take account of the changes to fscache's
indexing rewrite and reenable caching in 9p.

The following changes have been made:

 (1) The fscache_netfs struct is no more, and there's no need to register
     the filesystem as a whole.

 (2) The session cookie is now an fscache_volume cookie, allocated with
     fscache_acquire_volume().  That takes three parameters: a string
     representing the "volume" in the index, a string naming the cache to
     use (or NULL) and a u64 that conveys coherency metadata for the
     volume.

     For 9p, I've made it render the volume name string as:

	"9p,<devname>,<cachetag>"

     where the cachetag is replaced by the aname if it wasn't supplied.

     This probably needs rethinking a bit as the aname can have slashes in
     it.  It might be better to hash the cachetag and use the hash or I
     could substitute commas for the slashes or something.

 (3) The fscache_cookie_def is no more and needed information is passed
     directly to fscache_acquire_cookie().  The cache no longer calls back
     into the filesystem, but rather metadata changes are indicated at
     other times.

     fscache_acquire_cookie() is passed the same keying and coherency
     information as before.

 (4) The functions to set/reset/flush cookies are removed and
     fscache_use_cookie() and fscache_unuse_cookie() are used instead.

     fscache_use_cookie() is passed a flag to indicate if the cookie is
     opened for writing.  fscache_unuse_cookie() is passed updates for the
     metadata if we changed it (ie. if the file was opened for writing).

     These are called when the file is opened or closed.

 (5) wait_on_page_bit[_killable]() is replaced with the specific wait
     functions for the bits waited upon.

 (6) I've got rid of some of the 9p-specific cache helper functions and
     called things like fscache_relinquish_cookie() directly as they'll
     optimise away if v9fs_inode_cookie() returns an unconditional NULL
     (which will be the case if CONFIG_9P_FSCACHE=n).

 (7) v9fs_vfs_setattr() is made to call fscache_resize() to change the size
     of the cache object.

Notes:

 (A) We should call fscache_invalidate() if we detect that the server's
     copy of a file got changed by a third party, but I don't know where to
     do that.  We don't need to do that when allocating the cookie as we
     get a check-and-invalidate when we initially bind to the cache object.

 (B) The copy-to-cache-on-writeback side of things will be handled in
     separate patch.

Changes
=======
ver #3:
 - Canonicalise the cookie key and coherency data to make them
   endianness-independent.

ver #2:
 - Use gfpflags_allow_blocking() rather than using flag directly.
 - fscache_acquire_volume() now returns errors.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Dominique Martinet <asmadeus@codewreck.org>
cc: Eric Van Hensbergen <ericvh@gmail.com>
cc: Latchesar Ionkov <lucho@ionkov.net>
cc: v9fs-developer@lists.sourceforge.net
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819664645.215744.1555314582005286846.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906975017.143852.3459573173204394039.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967178512.1823006.17377493641569138183.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021573143.640689.3977487095697717967.stgit@warthog.procyon.org.uk/ # v4
2022-01-10 11:53:06 +00:00
Christian Brauner
3cb6ee9914 9p: only copy valid iattrs in 9P2000.L setattr implementation
The 9P2000.L setattr method v9fs_vfs_setattr_dotl() copies struct iattr
values without checking whether they are valid causing unitialized
values to be copied. The 9P2000 setattr method v9fs_vfs_setattr() method
gets this right. Check whether struct iattr fields are valid first
before copying in v9fs_vfs_setattr_dotl() too and make sure that all
other fields are set to 0 apart from {g,u}id which should be set to
INVALID_{G,U}ID. This ensure that they can be safely sent over the wire
or printed for debugging later on.

Link: https://lkml.kernel.org/r/20211129114434.3637938-1-brauner@kernel.org
Link: https://lkml.kernel.org/r/000000000000a0d53f05d1c72a4c%40google.com
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Cc: Dominique Martinet <asmadeus@codewreck.org>
Cc: stable@kernel.org
Cc: v9fs-developer@lists.sourceforge.net
Reported-by: syzbot+dfac92a50024b54acaa4@syzkaller.appspotmail.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
[Dominique: do not set a/mtime with just ATTR_A/MTIME as discussed]
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-01-10 10:00:09 +09:00
Zhang Mingyu
a7a427d154 9p: Use BUG_ON instead of if condition followed by BUG.
This issue was detected with the help of Coccinelle.

Link: https://lkml.kernel.org/r/20211112092547.9153-1-zhang.mingyu@zte.com.cn
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Zhang Mingyu <zhang.mingyu@zte.com.cn>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2022-01-10 10:00:09 +09:00
David Howells
2cee6fbb7f fscache: Remove the contents of the fscache driver, pending rewrite
Remove the code that comprises the fscache driver as it's going to be
substantially rewritten, with the majority of the code being erased in the
rewrite.

A small piece of linux/fscache.h is left as that is #included by a bunch of
network filesystems.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819578724.215744.18210619052245724238.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906884814.143852.6727245089843862889.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967077097.1823006.1377665951499979089.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021485548.640689.13876080567388696162.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:22:19 +00:00
David Howells
01491a7565 fscache, cachefiles: Disable configuration
Disable fscache and cachefiles in Kconfig whilst it is rewritten.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/163819576672.215744.12444272479560406780.stgit@warthog.procyon.org.uk/ # v1
Link: https://lore.kernel.org/r/163906882835.143852.11073015983885872901.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163967075113.1823006.277316290062782998.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/164021481179.640689.2004199594774033658.stgit@warthog.procyon.org.uk/ # v4
2022-01-07 09:21:44 +00:00
Changcheng Deng
90d6cf349c fs: 9p: remove unneeded variable
Fix the following coccicheck review:
./fs/9p/vfs_file.c: 117: 5-8: Unneeded variable

Remove unneeded variable used to store return value.

Link: https://lkml.kernel.org/r/20211109114343.132844-1-deng.changcheng@zte.com.cn
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Changcheng Deng <deng.changcheng@zte.com.cn>
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2021-12-18 21:04:50 +09:00
David Howells
78525c74d9 netfs, 9p, afs, ceph: Use folios
Convert the netfs helper library to use folios throughout, convert the 9p
and afs filesystems to use folios in their file I/O paths and convert the
ceph filesystem to use just enough folios to compile.

With these changes, afs passes -g quick xfstests.

Changes
=======
ver #5:
 - Got rid of folio_end{io,_read,_write}() and inlined the stuff it does
   instead (Willy decided he didn't want this after all).

ver #4:
 - Fixed a bug in afs_redirty_page() whereby it didn't set the next page
   index in the loop and returned too early.
 - Simplified a check in v9fs_vfs_write_folio_locked()[1].
 - Undid a change to afs_symlink_readpage()[1].
 - Used offset_in_folio() in afs_write_end()[1].
 - Changed from using page_endio() to folio_end{io,_read,_write}()[1].

ver #2:
 - Add 9p foliation.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Jeff Layton <jlayton@kernel.org>
Tested-by: Dominique Martinet <asmadeus@codewreck.org>
Tested-by: kafs-testing@auristor.com
cc: Matthew Wilcox (Oracle) <willy@infradead.org>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: Ilya Dryomov <idryomov@gmail.com>
cc: Dominique Martinet <asmadeus@codewreck.org>
cc: v9fs-developer@lists.sourceforge.net
cc: linux-afs@lists.infradead.org
cc: ceph-devel@vger.kernel.org
cc: linux-cachefs@redhat.com
Link: https://lore.kernel.org/r/YYKa3bfQZxK5/wDN@casper.infradead.org/ [1]
Link: https://lore.kernel.org/r/2408234.1628687271@warthog.procyon.org.uk/ # rfc
Link: https://lore.kernel.org/r/162877311459.3085614.10601478228012245108.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/162981153551.1901565.3124454657133703341.stgit@warthog.procyon.org.uk/
Link: https://lore.kernel.org/r/163005745264.2472992.9852048135392188995.stgit@warthog.procyon.org.uk/ # v2
Link: https://lore.kernel.org/r/163584187452.4023316.500389675405550116.stgit@warthog.procyon.org.uk/ # v3
Link: https://lore.kernel.org/r/163649328026.309189.1124218109373941936.stgit@warthog.procyon.org.uk/ # v4
Link: https://lore.kernel.org/r/163657852454.834781.9265101983152100556.stgit@warthog.procyon.org.uk/ # v5
2021-11-10 21:16:56 +00:00
Dominique Martinet
6e195b0f7c 9p: fix a bunch of checkpatch warnings
Sohaib Mohamed started a serie of tiny and incomplete checkpatch fixes but
seemingly stopped halfway -- take over and do most of it.
This is still missing net/9p/trans* and net/9p/protocol.c for a later
time...

Link: http://lkml.kernel.org/r/20211102134608.1588018-3-dominique.martinet@atmark-techno.com
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2021-11-04 21:04:25 +09:00
Dominique Martinet
b1843d2385 9p: set readahead and io size according to maxsize
having a readahead of 128k with a msize of 128k (with overhead) lead to
reading 124+4k everytime, making two roundtrips needlessly.

tune readahead according to msize when cache is enabled for better
performance

Link: http://lkml.kernel.org/r/20211104120323.2189376-1-asmadeus@codewreck.org
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
2021-11-04 21:04:04 +09:00