From: Jan Kara <jack@suse.cz>
To: Amir Goldstein <amir73il@gmail.com>
Cc: Jan Kara <jack@suse.cz>, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v3 20/20] fanotify: no external fh buffer in fanotify_name_event
Date: Wed, 15 Jul 2020 17:34:54 +0200 [thread overview]
Message-ID: <20200715153454.GO23073@quack2.suse.cz> (raw)
In-Reply-To: <20200708111156.24659-20-amir73il@gmail.com>
On Wed 08-07-20 14:11:55, Amir Goldstein wrote:
> The fanotify_fh struct has an inline buffer of size 12 which is enough
> to store the most common local filesystem file handles (e.g. ext4, xfs).
> For file handles that do not fit in the inline buffer (e.g. btrfs), an
> external buffer is allocated to store the file handle.
>
> When allocating a variable size fanotify_name_event, there is no point
> in allocating also an external fh buffer when file handle does not fit
> in the inline buffer.
>
> Check required size for encoding fh, preallocate an event buffer
> sufficient to contain both file handle and name and store the name after
> the file handle.
>
> At this time, when not reporting name in event, we still allocate
> the fixed size fanotify_fid_event and an external buffer for large
> file handles, but fanotify_alloc_name_event() has already been prepared
> to accept a NULL file_name.
>
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Just one tiny nit below:
> @@ -305,27 +323,34 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group,
> * Return 0 on failure to encode.
> */
> static int fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode,
> - gfp_t gfp)
> + unsigned int fh_len, gfp_t gfp)
> {
> - int dwords, type, bytes = 0;
> + int dwords, bytes, type = 0;
> char *ext_buf = NULL;
> void *buf = fh->buf;
> int err;
>
> fh->type = FILEID_ROOT;
> fh->len = 0;
> + fh->flags = 0;
> if (!inode)
> return 0;
>
> - dwords = 0;
> + /*
> + * !gpf means preallocated variable size fh, but fh_len could
> + * be zero in that case if encoding fh len failed.
> + */
> err = -ENOENT;
> - type = exportfs_encode_inode_fh(inode, NULL, &dwords, NULL);
> - if (!dwords)
> + if (!gfp)
> + bytes = fh_len;
> + else
> + bytes = fanotify_encode_fh_len(inode);
Any reason why proper fh len is not passed in by both callers? We could
then get rid of this 'if' and 'bytes' variable.
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2020-07-15 15:34 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-08 11:11 [PATCH v3 01/20] fsnotify: Rearrange fast path to minimise overhead when there is no watcher Amir Goldstein
2020-07-08 11:11 ` [PATCH v3 02/20] fsnotify: fold fsnotify() call into fsnotify_parent() Amir Goldstein
2020-07-08 11:11 ` [PATCH v3 03/20] fsnotify: return non const from fsnotify_data_inode() Amir Goldstein
2020-07-08 11:11 ` [PATCH v3 04/20] nfsd: use fsnotify_data_inode() to get the unlinked inode Amir Goldstein
2020-07-08 11:11 ` [PATCH v3 05/20] kernfs: do not call fsnotify() with name without a parent Amir Goldstein
2020-07-08 11:11 ` [PATCH v3 06/20] inotify: do not use objectid when comparing events Amir Goldstein
2020-07-08 11:11 ` [PATCH v3 07/20] fanotify: create overflow event type Amir Goldstein
2020-07-08 11:11 ` [PATCH v3 08/20] fanotify: break up fanotify_alloc_event() Amir Goldstein
2020-07-08 16:40 ` kernel test robot
[not found] ` <202007091516.gofG28uU%lkp@intel.com>
2020-07-09 9:03 ` Amir Goldstein
2020-07-08 11:11 ` [PATCH v3 09/20] fsnotify: pass dir argument to handle_event() callback Amir Goldstein
2020-07-08 11:11 ` [PATCH v3 10/20] fanotify: generalize the handling of extra event flags Amir Goldstein
2020-07-08 11:11 ` [PATCH v3 11/20] fanotify: generalize merge logic of events on dir Amir Goldstein
2020-07-08 11:11 ` [PATCH v3 12/20] fanotify: distinguish between fid encode error and null fid Amir Goldstein
2020-07-08 11:11 ` [PATCH v3 13/20] fanotify: generalize test for FAN_REPORT_FID Amir Goldstein
2020-07-08 11:11 ` [PATCH v3 14/20] fanotify: mask out special event flags from ignored mask Amir Goldstein
2020-07-08 11:11 ` [PATCH v3 15/20] fanotify: prepare for implicit event flags in mark mask Amir Goldstein
2020-07-08 11:11 ` [PATCH v3 16/20] fanotify: use FAN_EVENT_ON_CHILD as implicit flag on sb/mount/non-dir marks Amir Goldstein
2020-07-08 11:11 ` [PATCH v3 17/20] fanotify: remove event FAN_DIR_MODIFY Amir Goldstein
2020-07-08 11:11 ` [PATCH v3 18/20] fsnotify: add object type "child" to object type iterator Amir Goldstein
2020-07-08 11:11 ` [PATCH v3 19/20] fanotify: use struct fanotify_info to parcel the variable size buffer Amir Goldstein
2020-07-08 11:11 ` [PATCH v3 20/20] fanotify: no external fh buffer in fanotify_name_event Amir Goldstein
2020-07-15 15:34 ` Jan Kara [this message]
2020-07-15 16:05 ` Amir Goldstein
2020-07-15 16:22 ` Amir Goldstein
2020-07-15 16:24 ` Jan Kara
2020-07-15 17:44 ` Amir Goldstein
2020-07-08 11:11 ` [PATCH v3 00/20] Prep work for fanotify events with name info Amir Goldstein
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200715153454.GO23073@quack2.suse.cz \
--to=jack@suse.cz \
--cc=amir73il@gmail.com \
--cc=linux-fsdevel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).