AUTOSEL is wrong to select this commit without also selecting
29b00e609960 ("tmpfs: fix uninitialized return value in shmem_link")
which contains the tag
Fixes: 1062af920c07 ("tmpfs: fix link accounting when a tmpfile is linked in")
Please add 29b00e609960 for those 6 trees, or else omit 1062af920c07 for now.Thanks, Hugh On Wed, 13 Mar 2019, Sasha Levin wrote: > From: "Darrick J. Wong" <darrick.w...@oracle.com> > > [ Upstream commit 1062af920c07f5b54cf5060fde3339da6df0cf6b ] > > tmpfs has a peculiarity of accounting hard links as if they were > separate inodes: so that when the number of inodes is limited, as it is > by default, a user cannot soak up an unlimited amount of unreclaimable > dcache memory just by repeatedly linking a file. > > But when v3.11 added O_TMPFILE, and the ability to use linkat() on the > fd, we missed accommodating this new case in tmpfs: "df -i" shows that > an extra "inode" remains accounted after the file is unlinked and the fd > closed and the actual inode evicted. If a user repeatedly links > tmpfiles into a tmpfs, the limit will be hit (ENOSPC) even after they > are deleted. > > Just skip the extra reservation from shmem_link() in this case: there's > a sense in which this first link of a tmpfile is then cheaper than a > hard link of another file, but the accounting works out, and there's > still good limiting, so no need to do anything more complicated. > > Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1902182134370.7035@eggly.anvils > Fixes: f4e0c30c191 ("allow the temp files created by open() to be linked to") > Signed-off-by: Darrick J. Wong <darrick.w...@oracle.com> > Signed-off-by: Hugh Dickins <hu...@google.com> > Reported-by: Matej Kupljen <matej.kupl...@gmail.com> > Acked-by: Al Viro <v...@zeniv.linux.org.uk> > Signed-off-by: Andrew Morton <a...@linux-foundation.org> > Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> > Signed-off-by: Sasha Levin <sas...@kernel.org> > --- > mm/shmem.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/mm/shmem.c b/mm/shmem.c > index 5d07e0b1352f..7872e3b75e57 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -2852,10 +2852,14 @@ static int shmem_link(struct dentry *old_dentry, > struct inode *dir, struct dentr > * No ordinary (disk based) filesystem counts links as inodes; > * but each new link needs a new dentry, pinning lowmem, and > * tmpfs dentries cannot be pruned until they are unlinked. > + * But if an O_TMPFILE file is linked into the tmpfs, the > + * first link must skip that, to get the accounting right. > */ > - ret = shmem_reserve_inode(inode->i_sb); > - if (ret) > - goto out; > + if (inode->i_nlink) { > + ret = shmem_reserve_inode(inode->i_sb); > + if (ret) > + goto out; > + } > > dir->i_size += BOGO_DIRENT_SIZE; > inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode); > -- > 2.19.1
