summaryrefslogtreecommitdiff
path: root/Documentation/filesystems/tmpfs.rst
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2020-08-07 21:39:33 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-08-07 21:39:33 +0300
commit81e11336d97e7a4c25a65c302ef2bf9cd9808ed4 (patch)
tree44e069e0bb26068137a1bda7ca5125c5b068b4ab /Documentation/filesystems/tmpfs.rst
parent5631c5e0eb9035d92ceb20fcd9cdb7779a3f5cc7 (diff)
parent912c05720f00d039103d356a59c37dc7c3995e01 (diff)
downloadlinux-81e11336d97e7a4c25a65c302ef2bf9cd9808ed4.tar.xz
Merge branch 'akpm' (patches from Andrew)
Merge misc updates from Andrew Morton: - a few MM hotfixes - kthread, tools, scripts, ntfs and ocfs2 - some of MM Subsystems affected by this patch series: kthread, tools, scripts, ntfs, ocfs2 and mm (hofixes, pagealloc, slab-generic, slab, slub, kcsan, debug, pagecache, gup, swap, shmem, memcg, pagemap, mremap, mincore, sparsemem, vmalloc, kasan, pagealloc, hugetlb and vmscan). * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (162 commits) mm: vmscan: consistent update to pgrefill mm/vmscan.c: fix typo khugepaged: khugepaged_test_exit() check mmget_still_valid() khugepaged: retract_page_tables() remember to test exit khugepaged: collapse_pte_mapped_thp() protect the pmd lock khugepaged: collapse_pte_mapped_thp() flush the right range mm/hugetlb: fix calculation of adjust_range_if_pmd_sharing_possible mm: thp: replace HTTP links with HTTPS ones mm/page_alloc: fix memalloc_nocma_{save/restore} APIs mm/page_alloc.c: skip setting nodemask when we are in interrupt mm/page_alloc: fallbacks at most has 3 elements mm/page_alloc: silence a KASAN false positive mm/page_alloc.c: remove unnecessary end_bitidx for [set|get]_pfnblock_flags_mask() mm/page_alloc.c: simplify pageblock bitmap access mm/page_alloc.c: extract the common part in pfn_to_bitidx() mm/page_alloc.c: replace the definition of NR_MIGRATETYPE_BITS with PB_migratetype_bits mm/shuffle: remove dynamic reconfiguration mm/memory_hotplug: document why shuffle_zone() is relevant mm/page_alloc: remove nr_free_pagecache_pages() mm: remove vm_total_pages ...
Diffstat (limited to 'Documentation/filesystems/tmpfs.rst')
-rw-r--r--Documentation/filesystems/tmpfs.rst18
1 files changed, 18 insertions, 0 deletions
diff --git a/Documentation/filesystems/tmpfs.rst b/Documentation/filesystems/tmpfs.rst
index 4e95929301a5..c44f8b1d3cab 100644
--- a/Documentation/filesystems/tmpfs.rst
+++ b/Documentation/filesystems/tmpfs.rst
@@ -150,6 +150,22 @@ These options do not have any effect on remount. You can change these
parameters with chmod(1), chown(1) and chgrp(1) on a mounted filesystem.
+tmpfs has a mount option to select whether it will wrap at 32- or 64-bit inode
+numbers:
+
+======= ========================
+inode64 Use 64-bit inode numbers
+inode32 Use 32-bit inode numbers
+======= ========================
+
+On a 32-bit kernel, inode32 is implicit, and inode64 is refused at mount time.
+On a 64-bit kernel, CONFIG_TMPFS_INODE64 sets the default. inode64 avoids the
+possibility of multiple files with the same inode number on a single device;
+but risks glibc failing with EOVERFLOW once 33-bit inode numbers are reached -
+if a long-lived tmpfs is accessed by 32-bit applications so ancient that
+opening a file larger than 2GiB fails with EINVAL.
+
+
So 'mount -t tmpfs -o size=10G,nr_inodes=10k,mode=700 tmpfs /mytmpfs'
will give you tmpfs instance on /mytmpfs which can allocate 10GB
RAM/SWAP in 10240 inodes and it is only accessible by root.
@@ -161,3 +177,5 @@ RAM/SWAP in 10240 inodes and it is only accessible by root.
Hugh Dickins, 4 June 2007
:Updated:
KOSAKI Motohiro, 16 Mar 2010
+:Updated:
+ Chris Down, 13 July 2020