The patch titled Subject: tmpfs: support SEEK_DATA and SEEK_HOLE has been added to the -mm tree. Its filename is tmpfs-support-seek_data-and-seek_hole.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Hugh Dickins <hughd@xxxxxxxxxx> Subject: tmpfs: support SEEK_DATA and SEEK_HOLE It's quite easy for tmpfs to scan the radix_tree to support llseek's new SEEK_DATA and SEEK_HOLE options: so add them while the minutiae are still on my mind (in particular, the !PageUptodate-ness of pages fallocated but still unwritten). But I don't know who actually uses SEEK_DATA or SEEK_HOLE, and whether it would be of any use to them on tmpfs. This code adds 92 lines and 752 bytes on x86_64 - is that bloat or worthwhile? Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx> Cc: Josef Bacik <josef@xxxxxxxxxx> Cc: Andi Kleen <andi@xxxxxxxxxxxxxx> Cc: Andreas Dilger <adilger@xxxxxxxxx> Cc: Dave Chinner <david@xxxxxxxxxxxxx> Cc: Marco Stornelli <marco.stornelli@xxxxxxxxx> Cc: Jeff liu <jeff.liu@xxxxxxxxxx> Cc: Chris Mason <chris.mason@xxxxxxxxxx> Cc: Sunil Mushran <sunil.mushran@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/shmem.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 93 insertions(+), 1 deletion(-) diff -puN mm/shmem.c~tmpfs-support-seek_data-and-seek_hole mm/shmem.c --- a/mm/shmem.c~tmpfs-support-seek_data-and-seek_hole +++ a/mm/shmem.c @@ -439,6 +439,56 @@ void shmem_unlock_mapping(struct address } /* + * llseek SEEK_DATA or SEEK_HOLE through the radix_tree. + */ +static pgoff_t shmem_seek_hole_data(struct address_space *mapping, + pgoff_t index, pgoff_t end, int origin) +{ + struct page *page; + struct pagevec pvec; + pgoff_t indices[PAGEVEC_SIZE]; + bool done = false; + int i; + + pagevec_init(&pvec, 0); + pvec.nr = 1; /* start small: we may be there already */ + while (!done) { + pvec.nr = shmem_find_get_pages_and_swap(mapping, index, + pvec.nr, pvec.pages, indices); + if (!pvec.nr) { + if (origin == SEEK_DATA) + index = end; + break; + } + for (i = 0; i < pvec.nr; i++, index++) { + if (index < indices[i]) { + if (origin == SEEK_HOLE) { + done = true; + break; + } + index = indices[i]; + } + page = pvec.pages[i]; + if (page && !radix_tree_exceptional_entry(page)) { + if (!PageUptodate(page)) + page = NULL; + } + if (index >= end || + (page && origin == SEEK_DATA) || + (!page && origin == SEEK_HOLE)) { + done = true; + break; + } + } + shmem_deswap_pagevec(&pvec); + pagevec_release(&pvec); + pvec.nr = PAGEVEC_SIZE; + cond_resched(); + } + return index; +} + +/* * Remove range of pages and swap entries from radix tree, and free them. * If !unfalloc, truncate or punch hole; if unfalloc, undo failed fallocate. */ @@ -1674,6 +1724,48 @@ static ssize_t shmem_file_splice_read(st return error; } +static loff_t shmem_file_llseek(struct file *file, loff_t offset, int origin) +{ + struct address_space *mapping; + struct inode *inode; + pgoff_t start, end; + loff_t new_offset; + + if (origin != SEEK_DATA && origin != SEEK_HOLE) + return generic_file_llseek_size(file, offset, origin, + MAX_LFS_FILESIZE); + mapping = file->f_mapping; + inode = mapping->host; + mutex_lock(&inode->i_mutex); + /* We're holding i_mutex so we can access i_size directly */ + + if (offset < 0) + offset = -EINVAL; + else if (offset >= inode->i_size) + offset = -ENXIO; + else { + start = offset >> PAGE_CACHE_SHIFT; + end = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; + new_offset = shmem_seek_hole_data(mapping, start, end, origin); + new_offset <<= PAGE_CACHE_SHIFT; + if (new_offset > offset) { + if (new_offset < inode->i_size) + offset = new_offset; + else if (origin == SEEK_DATA) + offset = -ENXIO; + else + offset = inode->i_size; + } + } + + if (offset >= 0 && offset != file->f_pos) { + file->f_pos = offset; + file->f_version = 0; + } + mutex_unlock(&inode->i_mutex); + return offset; +} + static long shmem_fallocate(struct file *file, int mode, loff_t offset, loff_t len) { @@ -2667,7 +2759,7 @@ static const struct address_space_operat static const struct file_operations shmem_file_operations = { .mmap = shmem_mmap, #ifdef CONFIG_TMPFS - .llseek = generic_file_llseek, + .llseek = shmem_file_llseek, .read = do_sync_read, .write = do_sync_write, .aio_read = shmem_file_aio_read, _ Subject: Subject: tmpfs: support SEEK_DATA and SEEK_HOLE Patches currently in -mm which might be from hughd@xxxxxxxxxx are linux-next.patch mm-remove-swap-token-code.patch mm-vmscan-remove-lumpy-reclaim.patch mm-vmscan-do-not-stall-on-writeback-during-memory-compaction.patch mm-vmscan-remove-reclaim_mode_t.patch mm-mmapc-find_vma-remove-unnecessary-ifmm-check.patch mm-mmapc-find_vma-remove-unnecessary-ifmm-check-fix.patch mm-fork-fix-overflow-in-vma-length-when-copying-mmap-on-clone.patch mm-correctly-synchronize-rss-counters-at-exit-exec.patch bug-introduce-build_bug_on_invalid-macro.patch bug-completely-remove-code-generated-by-disabled-vm_bug_on.patch shmem-replace-page-if-mapping-excludes-its-zone.patch tmpfs-enable-nosec-optimization.patch tmpfs-optimize-clearing-when-writing.patch tmpfs-support-fallocate-falloc_fl_punch_hole.patch mm-fs-route-madv_remove-to-falloc_fl_punch_hole.patch mm-fs-remove-truncate_range.patch tmpfs-support-fallocate-preallocation.patch tmpfs-undo-fallocation-on-failure.patch tmpfs-quit-when-fallocate-fills-memory.patch tmpfs-support-seek_data-and-seek_hole.patch memcg-fix-change-behavior-of-shared-anon-at-moving-task.patch memcg-swap-mem_cgroup_move_swap_account-never-needs-fixup.patch memcg-swap-use-mem_cgroup_uncharge_swap.patch mm-memcg-scanning_global_lru-means-mem_cgroup_disabled.patch mm-memcg-move-reclaim_stat-into-lruvec.patch mm-push-lru-index-into-shrink_active_list.patch mm-push-lru-index-into-shrink_active_list-fix.patch mm-mark-mm-inline-functions-as-__always_inline.patch mm-remove-lru-type-checks-from-__isolate_lru_page.patch mm-memcg-kill-mem_cgroup_lru_del.patch mm-memcg-use-vm_swappiness-from-target-memory-cgroup.patch memcg-add-mlock-statistic-in-memorystat.patch memcg-add-mlock-statistic-in-memorystat-fix.patch mm-vmscan-store-priority-in-struct-scan_control.patch mm-add-link-from-struct-lruvec-to-struct-zone.patch mm-vmscan-push-lruvec-pointer-into-isolate_lru_pages.patch mm-vmscan-push-zone-pointer-into-shrink_page_list.patch mm-vmscan-remove-update_isolated_counts.patch mm-vmscan-push-lruvec-pointer-into-putback_inactive_pages.patch mm-vmscan-replace-zone_nr_lru_pages-with-get_lruvec_size.patch mm-vmscan-push-lruvec-pointer-into-inactive_list_is_low.patch mm-vmscan-push-lruvec-pointer-into-shrink_list.patch mm-vmscan-push-lruvec-pointer-into-get_scan_count.patch mm-vmscan-push-lruvec-pointer-into-should_continue_reclaim.patch mm-vmscan-kill-struct-mem_cgroup_zone.patch mm-huge_memoryc-use-lockdep_assert_held.patch proc-clean-up-proc-pid-environ-handling.patch proc-remove-mm_for_maps.patch proc-use-mm_access-instead-of-ptrace_may_access.patch proc-report-file-anon-bit-in-proc-pid-pagemap.patch proc-use-is_err_or_null.patch fork-call-complete_vfork_done-after-clearing-child_tid-and-flushing-rss-counters.patch prio_tree-debugging-patch.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html