diff options
author | David Howells <dhowells@redhat.com> | 2022-12-02 15:12:41 +0100 |
---|---|---|
committer | David Howells <dhowells@redhat.com> | 2023-12-24 16:08:51 +0100 |
commit | a34847d4b73c3a98b565b1d1cc6e1b70c661e18b (patch) | |
tree | 7d8a291a082ef312e523092cadec63abeb65b082 /fs/afs | |
parent | netfs: Add a ->free_subrequest() op (diff) | |
download | linux-a34847d4b73c3a98b565b1d1cc6e1b70c661e18b.tar.xz linux-a34847d4b73c3a98b565b1d1cc6e1b70c661e18b.zip |
afs: Don't use folio->private to record partial modification
AFS currently uses folio->private to store the range of bytes within a
folio that have been modified - the idea being that if we have, say, a 2MiB
folio and someone writes a single byte, we only have to write back that
single page and not the whole 2MiB folio - thereby saving on network
bandwidth.
Remove this, at least for now, and accept the extra network load (which
doesn't matter in the common case of writing a whole file at a time from
beginning to end).
This makes folio->private available for netfslib to use.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
cc: linux-cachefs@redhat.com
cc: linux-fsdevel@vger.kernel.org
cc: linux-mm@kvack.org
Diffstat (limited to 'fs/afs')
-rw-r--r-- | fs/afs/file.c | 67 | ||||
-rw-r--r-- | fs/afs/internal.h | 56 | ||||
-rw-r--r-- | fs/afs/write.c | 188 |
3 files changed, 38 insertions, 273 deletions
diff --git a/fs/afs/file.c b/fs/afs/file.c index 9142fda7dbd6..0d783e5b2147 100644 --- a/fs/afs/file.c +++ b/fs/afs/file.c @@ -387,63 +387,6 @@ const struct netfs_request_ops afs_req_ops = { }; /* - * Adjust the dirty region of the page on truncation or full invalidation, - * getting rid of the markers altogether if the region is entirely invalidated. - */ -static void afs_invalidate_dirty(struct folio *folio, size_t offset, - size_t length) -{ - struct afs_vnode *vnode = AFS_FS_I(folio_inode(folio)); - unsigned long priv; - unsigned int f, t, end = offset + length; - - priv = (unsigned long)folio_get_private(folio); - - /* we clean up only if the entire page is being invalidated */ - if (offset == 0 && length == folio_size(folio)) - goto full_invalidate; - - /* If the page was dirtied by page_mkwrite(), the PTE stays writable - * and we don't get another notification to tell us to expand it - * again. - */ - if (afs_is_folio_dirty_mmapped(priv)) - return; - - /* We may need to shorten the dirty region */ - f = afs_folio_dirty_from(folio, priv); - t = afs_folio_dirty_to(folio, priv); - - if (t <= offset || f >= end) - return; /* Doesn't overlap */ - - if (f < offset && t > end) - return; /* Splits the dirty region - just absorb it */ - - if (f >= offset && t <= end) - goto undirty; - - if (f < offset) - t = offset; - else - f = end; - if (f == t) - goto undirty; - - priv = afs_folio_dirty(folio, f, t); - folio_change_private(folio, (void *)priv); - trace_afs_folio_dirty(vnode, tracepoint_string("trunc"), folio); - return; - -undirty: - trace_afs_folio_dirty(vnode, tracepoint_string("undirty"), folio); - folio_clear_dirty_for_io(folio); -full_invalidate: - trace_afs_folio_dirty(vnode, tracepoint_string("inval"), folio); - folio_detach_private(folio); -} - -/* * invalidate part or all of a page * - release a page and clean up its private data if offset is 0 (indicating * the entire page) @@ -453,11 +396,6 @@ static void afs_invalidate_folio(struct folio *folio, size_t offset, { _enter("{%lu},%zu,%zu", folio->index, offset, length); - BUG_ON(!folio_test_locked(folio)); - - if (folio_get_private(folio)) - afs_invalidate_dirty(folio, offset, length); - folio_wait_fscache(folio); _leave(""); } @@ -485,11 +423,6 @@ static bool afs_release_folio(struct folio *folio, gfp_t gfp) fscache_note_page_release(afs_vnode_cache(vnode)); #endif - if (folio_test_private(folio)) { - trace_afs_folio_dirty(vnode, tracepoint_string("rel"), folio); - folio_detach_private(folio); - } - /* Indicate that the folio can be released */ _leave(" = T"); return true; diff --git a/fs/afs/internal.h b/fs/afs/internal.h index b77797559e27..a7c8d1d702ee 100644 --- a/fs/afs/internal.h +++ b/fs/afs/internal.h @@ -894,62 +894,6 @@ static inline void afs_invalidate_cache(struct afs_vnode *vnode, unsigned int fl i_size_read(&vnode->netfs.inode), flags); } -/* - * We use folio->private to hold the amount of the folio that we've written to, - * splitting the field into two parts. However, we need to represent a range - * 0...FOLIO_SIZE, so we reduce the resolution if the size of the folio - * exceeds what we can encode. - */ -#ifdef CONFIG_64BIT -#define __AFS_FOLIO_PRIV_MASK 0x7fffffffUL -#define __AFS_FOLIO_PRIV_SHIFT 32 -#define __AFS_FOLIO_PRIV_MMAPPED 0x80000000UL -#else -#define __AFS_FOLIO_PRIV_MASK 0x7fffUL -#define __AFS_FOLIO_PRIV_SHIFT 16 -#define __AFS_FOLIO_PRIV_MMAPPED 0x8000UL -#endif - -static inline unsigned int afs_folio_dirty_resolution(struct folio *folio) -{ - int shift = folio_shift(folio) - (__AFS_FOLIO_PRIV_SHIFT - 1); - return (shift > 0) ? shift : 0; -} - -static inline size_t afs_folio_dirty_from(struct folio *folio, unsigned long priv) -{ - unsigned long x = priv & __AFS_FOLIO_PRIV_MASK; - - /* The lower bound is inclusive */ - return x << afs_folio_dirty_resolution(folio); -} - -static inline size_t afs_folio_dirty_to(struct folio *folio, unsigned long priv) -{ - unsigned long x = (priv >> __AFS_FOLIO_PRIV_SHIFT) & __AFS_FOLIO_PRIV_MASK; - - /* The upper bound is immediately beyond the region */ - return (x + 1) << afs_folio_dirty_resolution(folio); -} - -static inline unsigned long afs_folio_dirty(struct folio *folio, size_t from, size_t to) -{ - unsigned int res = afs_folio_dirty_resolution(folio); - from >>= res; - to = (to - 1) >> res; - return (to << __AFS_FOLIO_PRIV_SHIFT) | from; -} - -static inline unsigned long afs_folio_dirty_mmapped(unsigned long priv) -{ - return priv | __AFS_FOLIO_PRIV_MMAPPED; -} - -static inline bool afs_is_folio_dirty_mmapped(unsigned long priv) -{ - return priv & __AFS_FOLIO_PRIV_MMAPPED; -} - #include <trace/events/afs.h> /*****************************************************************************/ diff --git a/fs/afs/write.c b/fs/afs/write.c index e40cf8e7543a..80daf28d8f8b 100644 --- a/fs/afs/write.c +++ b/fs/afs/write.c @@ -16,7 +16,8 @@ static int afs_writepages_region(struct address_space *mapping, struct writeback_control *wbc, - loff_t start, loff_t end, loff_t *_next, + unsigned long long start, + unsigned long long end, loff_t *_next, bool max_one_loop); static void afs_write_to_cache(struct afs_vnode *vnode, loff_t start, size_t len, @@ -35,25 +36,6 @@ static void afs_folio_start_fscache(bool caching, struct folio *folio) #endif /* - * Flush out a conflicting write. This may extend the write to the surrounding - * pages if also dirty and contiguous to the conflicting region.. - */ -static int afs_flush_conflicting_write(struct address_space *mapping, - struct folio *folio) -{ - struct writeback_control wbc = { - .sync_mode = WB_SYNC_ALL, - .nr_to_write = LONG_MAX, - .range_start = folio_pos(folio), - .range_end = LLONG_MAX, - }; - loff_t next; - - return afs_writepages_region(mapping, &wbc, folio_pos(folio), LLONG_MAX, - &next, true); -} - -/* * prepare to perform part of a write to a page */ int afs_write_begin(struct file *file, struct address_space *mapping, @@ -62,10 +44,6 @@ int afs_write_begin(struct file *file, struct address_space *mapping, { struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); struct folio *folio; - unsigned long priv; - unsigned f, from; - unsigned t, to; - pgoff_t index; int ret; _enter("{%llx:%llu},%llx,%x", @@ -79,49 +57,20 @@ int afs_write_begin(struct file *file, struct address_space *mapping, if (ret < 0) return ret; - index = folio_index(folio); - from = pos - index * PAGE_SIZE; - to = from + len; - try_again: /* See if this page is already partially written in a way that we can * merge the new write with. */ - if (folio_test_private(folio)) { - priv = (unsigned long)folio_get_private(folio); - f = afs_folio_dirty_from(folio, priv); - t = afs_folio_dirty_to(folio, priv); - ASSERTCMP(f, <=, t); - - if (folio_test_writeback(folio)) { - trace_afs_folio_dirty(vnode, tracepoint_string("alrdy"), folio); - folio_unlock(folio); - goto wait_for_writeback; - } - /* If the file is being filled locally, allow inter-write - * spaces to be merged into writes. If it's not, only write - * back what the user gives us. - */ - if (!test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags) && - (to < f || from > t)) - goto flush_conflicting_write; + if (folio_test_writeback(folio)) { + trace_afs_folio_dirty(vnode, tracepoint_string("alrdy"), folio); + folio_unlock(folio); + goto wait_for_writeback; } *_page = folio_file_page(folio, pos / PAGE_SIZE); _leave(" = 0"); return 0; - /* The previous write and this write aren't adjacent or overlapping, so - * flush the page out. - */ -flush_conflicting_write: - trace_afs_folio_dirty(vnode, tracepoint_string("confl"), folio); - folio_unlock(folio); - - ret = afs_flush_conflicting_write(mapping, folio); - if (ret < 0) - goto error; - wait_for_writeback: ret = folio_wait_writeback_killable(folio); if (ret < 0) @@ -147,9 +96,6 @@ int afs_write_end(struct file *file, struct address_space *mapping, { struct folio *folio = page_folio(subpage); struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); - unsigned long priv; - unsigned int f, from = offset_in_folio(folio, pos); - unsigned int t, to = from + copied; loff_t i_size, write_end_pos; _enter("{%llx:%llu},{%lx}", @@ -179,23 +125,6 @@ int afs_write_end(struct file *file, struct address_space *mapping, fscache_update_cookie(afs_vnode_cache(vnode), NULL, &write_end_pos); } - if (folio_test_private(folio)) { - priv = (unsigned long)folio_get_private(folio); - f = afs_folio_dirty_from(folio, priv); - t = afs_folio_dirty_to(folio, priv); - if (from < f) - f = from; - if (to > t) - t = to; - priv = afs_folio_dirty(folio, f, t); - folio_change_private(folio, (void *)priv); - trace_afs_folio_dirty(vnode, tracepoint_string("dirty+"), folio); - } else { - priv = afs_folio_dirty(folio, from, to); - folio_attach_private(folio, (void *)priv); - trace_afs_folio_dirty(vnode, tracepoint_string("dirty"), folio); - } - if (folio_mark_dirty(folio)) _debug("dirtied %lx", folio_index(folio)); @@ -300,7 +229,6 @@ static void afs_pages_written_back(struct afs_vnode *vnode, loff_t start, unsign } trace_afs_folio_dirty(vnode, tracepoint_string("clear"), folio); - folio_detach_private(folio); folio_end_writeback(folio); } @@ -454,17 +382,12 @@ static void afs_extend_writeback(struct address_space *mapping, long *_count, loff_t start, loff_t max_len, - bool new_content, bool caching, - unsigned int *_len) + size_t *_len) { struct folio_batch fbatch; struct folio *folio; - unsigned long priv; - unsigned int psize, filler = 0; - unsigned int f, t; - loff_t len = *_len; - pgoff_t index = (start + len) / PAGE_SIZE; + pgoff_t index = (start + *_len) / PAGE_SIZE; bool stop = true; unsigned int i; @@ -492,7 +415,7 @@ static void afs_extend_writeback(struct address_space *mapping, continue; } - /* Has the page moved or been split? */ + /* Has the folio moved or been split? */ if (unlikely(folio != xas_reload(&xas))) { folio_put(folio); break; @@ -510,24 +433,13 @@ static void afs_extend_writeback(struct address_space *mapping, break; } - psize = folio_size(folio); - priv = (unsigned long)folio_get_private(folio); - f = afs_folio_dirty_from(folio, priv); - t = afs_folio_dirty_to(folio, priv); - if (f != 0 && !new_content) { - folio_unlock(folio); - folio_put(folio); - break; - } - - len += filler + t; - filler = psize - t; - if (len >= max_len || *_count <= 0) + index += folio_nr_pages(folio); + *_count -= folio_nr_pages(folio); + *_len += folio_size(folio); + stop = false; + if (*_len >= max_len || *_count <= 0) stop = true; - else if (t == psize || new_content) - stop = false; - index += folio_nr_pages(folio); if (!folio_batch_add(&fbatch, folio)) break; if (stop) @@ -553,16 +465,12 @@ static void afs_extend_writeback(struct address_space *mapping, if (folio_start_writeback(folio)) BUG(); afs_folio_start_fscache(caching, folio); - - *_count -= folio_nr_pages(folio); folio_unlock(folio); } folio_batch_release(&fbatch); cond_resched(); } while (!stop); - - *_len = len; } /* @@ -572,14 +480,13 @@ static void afs_extend_writeback(struct address_space *mapping, static ssize_t afs_write_back_from_locked_folio(struct address_space *mapping, struct writeback_control *wbc, struct folio *folio, - loff_t start, loff_t end) + unsigned long long start, + unsigned long long end) { struct afs_vnode *vnode = AFS_FS_I(mapping->host); struct iov_iter iter; - unsigned long priv; - unsigned int offset, to, len, max_len; - loff_t i_size = i_size_read(&vnode->netfs.inode); - bool new_content = test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags); + unsigned long long i_size = i_size_read(&vnode->netfs.inode); + size_t len, max_len; bool caching = fscache_cookie_enabled(afs_vnode_cache(vnode)); long count = wbc->nr_to_write; int ret; @@ -597,13 +504,9 @@ static ssize_t afs_write_back_from_locked_folio(struct address_space *mapping, * immediately lockable, is not dirty or is missing, or we reach the * end of the range. */ - priv = (unsigned long)folio_get_private(folio); - offset = afs_folio_dirty_from(folio, priv); - to = afs_folio_dirty_to(folio, priv); trace_afs_folio_dirty(vnode, tracepoint_string("store"), folio); - len = to - offset; - start += offset; + len = folio_size(folio); if (start < i_size) { /* Trim the write to the EOF; the extra data is ignored. Also * put an upper limit on the size of a single storedata op. @@ -612,12 +515,10 @@ static ssize_t afs_write_back_from_locked_folio(struct address_space *mapping, max_len = min_t(unsigned long long, max_len, end - start + 1); max_len = min_t(unsigned long long, max_len, i_size - start); - if (len < max_len && - (to == folio_size(folio) || new_content)) + if (len < max_len) afs_extend_writeback(mapping, vnode, &count, - start, max_len, new_content, - caching, &len); - len = min_t(loff_t, len, max_len); + start, max_len, caching, &len); + len = min_t(unsigned long long, len, i_size - start); } /* We now have a contiguous set of dirty pages, each with writeback @@ -627,7 +528,7 @@ static ssize_t afs_write_back_from_locked_folio(struct address_space *mapping, folio_unlock(folio); if (start < i_size) { - _debug("write back %x @%llx [%llx]", len, start, i_size); + _debug("write back %zx @%llx [%llx]", len, start, i_size); /* Speculatively write to the cache. We have to fix this up * later if the store fails. @@ -637,7 +538,7 @@ static ssize_t afs_write_back_from_locked_folio(struct address_space *mapping, iov_iter_xarray(&iter, ITER_SOURCE, &mapping->i_pages, start, len); ret = afs_store_data(vnode, &iter, start, false); } else { - _debug("write discard %x @%llx [%llx]", len, start, i_size); + _debug("write discard %zx @%llx [%llx]", len, start, i_size); /* The dirty region was entirely beyond the EOF. */ fscache_clear_page_bits(mapping, start, len, caching); @@ -693,7 +594,8 @@ static ssize_t afs_write_back_from_locked_folio(struct address_space *mapping, */ static int afs_writepages_region(struct address_space *mapping, struct writeback_control *wbc, - loff_t start, loff_t end, loff_t *_next, + unsigned long long start, + unsigned long long end, loff_t *_next, bool max_one_loop) { struct folio *folio; @@ -905,7 +807,6 @@ vm_fault_t afs_page_mkwrite(struct vm_fault *vmf) struct inode *inode = file_inode(file); struct afs_vnode *vnode = AFS_FS_I(inode); struct afs_file *af = file->private_data; - unsigned long priv; vm_fault_t ret = VM_FAULT_RETRY; _enter("{{%llx:%llu}},{%lx}", vnode->fid.vid, vnode->fid.vnode, folio_index(folio)); @@ -929,24 +830,15 @@ vm_fault_t afs_page_mkwrite(struct vm_fault *vmf) if (folio_lock_killable(folio) < 0) goto out; - /* We mustn't change folio->private until writeback is complete as that - * details the portion of the page we need to write back and we might - * need to redirty the page if there's a problem. - */ if (folio_wait_writeback_killable(folio) < 0) { folio_unlock(folio); goto out; } - priv = afs_folio_dirty(folio, 0, folio_size(folio)); - priv = afs_folio_dirty_mmapped(priv); - if (folio_test_private(folio)) { - folio_change_private(folio, (void *)priv); + if (folio_test_dirty(folio)) trace_afs_folio_dirty(vnode, tracepoint_string("mkwrite+"), folio); - } else { - folio_attach_private(folio, (void *)priv); + else trace_afs_folio_dirty(vnode, tracepoint_string("mkwrite"), folio); - } file_update_time(file); ret = VM_FAULT_LOCKED; @@ -991,30 +883,26 @@ int afs_launder_folio(struct folio *folio) struct afs_vnode *vnode = AFS_FS_I(folio_inode(folio)); struct iov_iter iter; struct bio_vec bv; - unsigned long priv; - unsigned int f, t; + unsigned long long fend, i_size = vnode->netfs.inode.i_size; + size_t len; int ret = 0; _enter("{%lx}", folio->index); - priv = (unsigned long)folio_get_private(folio); - if (folio_clear_dirty_for_io(folio)) { - f = 0; - t = folio_size(folio); - if (folio_test_private(folio)) { - f = afs_folio_dirty_from(folio, priv); - t = afs_folio_dirty_to(folio, priv); - } + if (folio_clear_dirty_for_io(folio) && folio_pos(folio) < i_size) { + len = folio_size(folio); + fend = folio_pos(folio) + len; + if (vnode->netfs.inode.i_size < fend) + len = fend - i_size; - bvec_set_folio(&bv, folio, t - f, f); - iov_iter_bvec(&iter, ITER_SOURCE, &bv, 1, bv.bv_len); + bvec_set_folio(&bv, folio, len, 0); + iov_iter_bvec(&iter, WRITE, &bv, 1, len); trace_afs_folio_dirty(vnode, tracepoint_string("launder"), folio); - ret = afs_store_data(vnode, &iter, folio_pos(folio) + f, true); + ret = afs_store_data(vnode, &iter, folio_pos(folio), true); } trace_afs_folio_dirty(vnode, tracepoint_string("laundered"), folio); - folio_detach_private(folio); folio_wait_fscache(folio); return ret; } |