Jeff Layton <jlayton@xxxxxxxxxx> writes: > The current code will update the mtime and then try to get caps to > handle the write. If we end up having to request caps from the MDS, then > the mtime in the cap grant will clobber the updated mtime and it'll be > lost. > > This is most noticable when two clients are alternately writing to the > same file. Fw caps are continually being granted and revoked, and the > mtime ends up stuck because the updated mtimes are always being > overwritten with the old one. > > Fix this by changing the order of operations in ceph_write_iter. Get the > caps much earlier, and only update the times afterward. Also, make sure > we check the NEARFULL conditions before making any changes to the inode. > > URL: https://tracker.ceph.com/issues/46574 > Reported-by: Jozef Kováč <kovac@xxxxxxxxxxxxxxx> > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> > --- > fs/ceph/file.c | 34 +++++++++++++++++----------------- > 1 file changed, 17 insertions(+), 17 deletions(-) > > diff --git a/fs/ceph/file.c b/fs/ceph/file.c > index f55ca2c4c7de..5867acfc6a51 100644 > --- a/fs/ceph/file.c > +++ b/fs/ceph/file.c > @@ -1722,22 +1722,6 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from) > goto out; > } > > - err = file_remove_privs(file); > - if (err) > - goto out; > - > - err = file_update_time(file); > - if (err) > - goto out; > - > - inode_inc_iversion_raw(inode); > - > - if (ci->i_inline_version != CEPH_INLINE_NONE) { > - err = ceph_uninline_data(file, NULL); > - if (err < 0) > - goto out; > - } > - > down_read(&osdc->lock); > map_flags = osdc->osdmap->flags; > pool_flags = ceph_pg_pool_flags(osdc->osdmap, ci->i_layout.pool_id); > @@ -1748,6 +1732,12 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from) > goto out; > } > > + if (ci->i_inline_version != CEPH_INLINE_NONE) { > + err = ceph_uninline_data(file, NULL); > + if (err < 0) > + goto out; > + } > + > dout("aio_write %p %llx.%llx %llu~%zd getting caps. i_size %llu\n", > inode, ceph_vinop(inode), pos, count, i_size_read(inode)); > if (fi->fmode & CEPH_FILE_MODE_LAZY) > @@ -1759,6 +1749,16 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from) > if (err < 0) > goto out; > > + err = file_remove_privs(file); > + if (err) > + goto out_caps; > + > + err = file_update_time(file); > + if (err) > + goto out_caps; Unless I'm missing something (which happens quite frequently!) i_rwsem still needs to be released through either ceph_end_io_write() or ceph_end_io_direct(). And this isn't being done if we jump to out_caps (yeah, goto's spaghetti fun). Also, this patch is probably worth adding to stable@ too, although I haven't checked how easy is it to cherry-pick to older kernel versions. Cheers, -- Luis > + > + inode_inc_iversion_raw(inode); > + > dout("aio_write %p %llx.%llx %llu~%zd got cap refs on %s\n", > inode, ceph_vinop(inode), pos, count, ceph_cap_string(got)); > > @@ -1822,7 +1822,7 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from) > if (ceph_quota_is_max_bytes_approaching(inode, iocb->ki_pos)) > ceph_check_caps(ci, 0, NULL); > } > - > +out_caps: > dout("aio_write %p %llx.%llx %llu~%u dropping cap refs on %s\n", > inode, ceph_vinop(inode), pos, (unsigned)count, > ceph_cap_string(got)); > -- > > 2.31.1 >
