On Sun 04-09-22 18:46:39, Amir Goldstein wrote: > Add section about evictable inode marks and example use case. > Add possible error case EEXIST related to evictable marks. > > Reviewed-by: Matthew Bobrowski <repnop@xxxxxxxxxx> > Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx> > --- > > Hi Alex, > > This is an update for a new fanotify feature in v5.19. > Please wait to see if Jan has any commetns before merging. Besides the mistakes Alejandro already found the patch looks good to me. Honza > > Thanks, > Amir. > > man2/fanotify_mark.2 | 50 ++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 50 insertions(+) > > diff --git a/man2/fanotify_mark.2 b/man2/fanotify_mark.2 > index 2696a803a..757ad9159 100644 > --- a/man2/fanotify_mark.2 > +++ b/man2/fanotify_mark.2 > @@ -153,6 +153,44 @@ If this flag is not set, > the ignore mask is cleared when a modify event occurs > for the ignored file or directory. > .PP > +.TP > +.BR FAN_MARK_EVICTABLE " (since Linux 5.19)" > +.\" commit 5f9d3bd520261fd7a850818c71809fd580e0f30c > +When an inode mark is created with this flag, > +the inode object will not be pinned to the inode cache. > +Therefore, allowing the inode object to be evicted from the inode cache > +when the memory pressure on the system is high. > +The eviction of the inode object results in the evictable mark also > +being lost. > +When the mask of an evictable inode mark is updated > +without using the > +.B FAN_MARK_EVICATBLE > +flag, > +the marked inode is pinned to inode cache > +and the mark is no longer evictable. > +When the mask of a non-evictable inode mark is updated > +with the > +.B FAN_MARK_EVICTABLE > +flag, > +the inode mark remains non-evictable > +and the update fails with > +.B EEXIST > +error. > +Mounts and filesystems are not evictable, > +so an attempt to create an evictable mount or filesystem mark > +will results with > +.B EINVAL > +error. > +For example, > +inode marks can be used in combination with mount marks > +to reduce the amount of events from noninteresting paths. > +The event listener reads events, > +checks if the path reported in the event is of interest > +and if it is not, > +the listener sets a mark with an ignore mask on the directory. > +Evictable inode marks allow using this method for a large number of directories > +without the concern of pinning all inodes and exhausting the system's memory. > +.PP > .I mask > defines which events shall be listened for (or which shall be ignored). > It is a bit mask composed of the following values: > @@ -409,6 +447,18 @@ is neither > .B AT_FDCWD > nor a valid file descriptor. > .TP > +.B EEXIST > +The filesystem object indicated by > +.I dirfd > +and > +.I pathname > +has a mark that was updated without the > +.B FAN_MARK_EVICTABLE > +flag, > +and the user attempted to update the mark with > +.B FAN_MARK_EVICTABLE > +flag. > +.TP > .B EINVAL > An invalid value was passed in > .I flags > -- > 2.25.1 > -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
