From 4fbf4291aa15926cd4fdca0ffe9122e89d0459db Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 19 Nov 2009 18:11:04 +0000 Subject: FS-Cache: Allow the current state of all objects to be dumped Allow the current state of all fscache objects to be dumped by doing: cat /proc/fs/fscache/objects By default, all objects and all fields will be shown. This can be restricted by adding a suitable key to one of the caller's keyrings (such as the session keyring): keyctl add user fscache:objlist "" @s The are: K Show hexdump of object key (don't show if not given) A Show hexdump of object aux data (don't show if not given) And paired restrictions: C Show objects that have a cookie c Show objects that don't have a cookie B Show objects that are busy b Show objects that aren't busy W Show objects that have pending writes w Show objects that don't have pending writes R Show objects that have outstanding reads r Show objects that don't have outstanding reads S Show objects that have slow work queued s Show objects that don't have slow work queued If neither side of a restriction pair is given, then both are implied. For example: keyctl add user fscache:objlist KB @s shows objects that are busy, and lists their object keys, but does not dump their auxiliary data. It also implies "CcWwRrSs", but as 'B' is given, 'b' is not implied. Signed-off-by: David Howells --- fs/cachefiles/rdwr.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'fs/cachefiles/rdwr.c') diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c index a69787e7dd9..3304646dae8 100644 --- a/fs/cachefiles/rdwr.c +++ b/fs/cachefiles/rdwr.c @@ -333,7 +333,8 @@ int cachefiles_read_or_alloc_page(struct fscache_retrieval *op, shift = PAGE_SHIFT - inode->i_sb->s_blocksize_bits; - op->op.flags = FSCACHE_OP_FAST; + op->op.flags &= FSCACHE_OP_KEEP_FLAGS; + op->op.flags |= FSCACHE_OP_FAST; op->op.processor = cachefiles_read_copier; pagevec_init(&pagevec, 0); @@ -639,7 +640,8 @@ int cachefiles_read_or_alloc_pages(struct fscache_retrieval *op, pagevec_init(&pagevec, 0); - op->op.flags = FSCACHE_OP_FAST; + op->op.flags &= FSCACHE_OP_KEEP_FLAGS; + op->op.flags |= FSCACHE_OP_FAST; op->op.processor = cachefiles_read_copier; INIT_LIST_HEAD(&backpages); -- cgit v1.2.3-70-g09d2 From a17754fb8c28af19cd70dcbec6d5b0773b94e0c1 Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 19 Nov 2009 18:11:52 +0000 Subject: CacheFiles: Don't write a full page if there's only a partial page to cache cachefiles_write_page() writes a full page to the backing file for the last page of the netfs file, even if the netfs file's last page is only a partial page. This causes the EOF on the backing file to be extended beyond the EOF of the netfs, and thus the backing file will be truncated by cachefiles_attr_changed() called from cachefiles_lookup_object(). So we need to limit the write we make to the backing file on that last page such that it doesn't push the EOF too far. Also, if a backing file that has a partial page at the end is expanded, we discard the partial page and refetch it on the basis that we then have a hole in the file with invalid data, and should the power go out... A better way to deal with this could be to record a note that the partial page contains invalid data until the correct data is written into it. This isn't a problem for netfs's that discard the whole backing file if the file size changes (such as NFS). Signed-off-by: David Howells --- fs/cachefiles/interface.c | 20 +++++++++++++++++--- fs/cachefiles/rdwr.c | 23 +++++++++++++++++++---- include/linux/fscache-cache.h | 3 +++ 3 files changed, 39 insertions(+), 7 deletions(-) (limited to 'fs/cachefiles/rdwr.c') diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c index dd7f852746c..8e67abf0598 100644 --- a/fs/cachefiles/interface.c +++ b/fs/cachefiles/interface.c @@ -404,12 +404,26 @@ static int cachefiles_attr_changed(struct fscache_object *_object) if (oi_size == ni_size) return 0; - newattrs.ia_size = ni_size; - newattrs.ia_valid = ATTR_SIZE; - cachefiles_begin_secure(cache, &saved_cred); mutex_lock(&object->backer->d_inode->i_mutex); + + /* if there's an extension to a partial page at the end of the backing + * file, we need to discard the partial page so that we pick up new + * data after it */ + if (oi_size & ~PAGE_MASK && ni_size > oi_size) { + _debug("discard tail %llx", oi_size); + newattrs.ia_valid = ATTR_SIZE; + newattrs.ia_size = oi_size & PAGE_MASK; + ret = notify_change(object->backer, &newattrs); + if (ret < 0) + goto truncate_failed; + } + + newattrs.ia_valid = ATTR_SIZE; + newattrs.ia_size = ni_size; ret = notify_change(object->backer, &newattrs); + +truncate_failed: mutex_unlock(&object->backer->d_inode->i_mutex); cachefiles_end_secure(cache, saved_cred); diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c index 3304646dae8..5a84fd7109a 100644 --- a/fs/cachefiles/rdwr.c +++ b/fs/cachefiles/rdwr.c @@ -803,7 +803,8 @@ int cachefiles_write_page(struct fscache_storage *op, struct page *page) struct cachefiles_cache *cache; mm_segment_t old_fs; struct file *file; - loff_t pos; + loff_t pos, eof; + size_t len; void *data; int ret; @@ -837,15 +838,29 @@ int cachefiles_write_page(struct fscache_storage *op, struct page *page) ret = -EIO; if (file->f_op->write) { pos = (loff_t) page->index << PAGE_SHIFT; + + /* we mustn't write more data than we have, so we have + * to beware of a partial page at EOF */ + eof = object->fscache.store_limit_l; + len = PAGE_SIZE; + if (eof & ~PAGE_MASK) { + ASSERTCMP(pos, <, eof); + if (eof - pos < PAGE_SIZE) { + _debug("cut short %llx to %llx", + pos, eof); + len = eof - pos; + ASSERTCMP(pos + len, ==, eof); + } + } + data = kmap(page); old_fs = get_fs(); set_fs(KERNEL_DS); ret = file->f_op->write( - file, (const void __user *) data, PAGE_SIZE, - &pos); + file, (const void __user *) data, len, &pos); set_fs(old_fs); kunmap(page); - if (ret != PAGE_SIZE) + if (ret != len) ret = -EIO; } fput(file); diff --git a/include/linux/fscache-cache.h b/include/linux/fscache-cache.h index 907bb56c588..5db50002f3b 100644 --- a/include/linux/fscache-cache.h +++ b/include/linux/fscache-cache.h @@ -395,6 +395,7 @@ struct fscache_object { struct rb_node objlist_link; /* link in global object list */ #endif pgoff_t store_limit; /* current storage limit */ + loff_t store_limit_l; /* current storage limit */ }; extern const char *fscache_object_states[]; @@ -439,6 +440,7 @@ void fscache_object_init(struct fscache_object *object, object->events = object->event_mask = 0; object->flags = 0; object->store_limit = 0; + object->store_limit_l = 0; object->cache = cache; object->cookie = cookie; object->parent = NULL; @@ -491,6 +493,7 @@ static inline void fscache_object_lookup_error(struct fscache_object *object) static inline void fscache_set_store_limit(struct fscache_object *object, loff_t i_size) { + object->store_limit_l = i_size; object->store_limit = i_size >> PAGE_SHIFT; if (i_size & ~PAGE_MASK) object->store_limit++; -- cgit v1.2.3-70-g09d2 From 5e929b33c3935ecb029b3e495356b2b8af432efa Mon Sep 17 00:00:00 2001 From: David Howells Date: Thu, 19 Nov 2009 18:11:55 +0000 Subject: CacheFiles: Handle truncate unlocking the page we're reading Handle truncate unlocking the page we're attempting to read from the backing device before the read has completed. This was causing reports like the following to occur: Pid: 4765, comm: kslowd Not tainted 2.6.30.1 #1 Call Trace: [] ? cachefiles_read_waiter+0xd9/0x147 [cachefiles] [] ? __wait_on_bit+0x60/0x6f [] ? __wake_up_common+0x3f/0x71 [] ? __wake_up+0x30/0x44 [] ? __wake_up_bit+0x28/0x2d [] ? ext3_truncate+0x4d7/0x8ed [ext3] [] ? pagevec_lookup+0x17/0x1f [] ? unmap_mapping_range+0x59/0x1ff [] ? __wake_up+0x30/0x44 [] ? vmtruncate+0xc2/0xe2 [] ? inode_setattr+0x22/0x10a [] ? ext3_setattr+0x17b/0x1e6 [ext3] [] ? notify_change+0x186/0x2c9 [] ? cachefiles_attr_changed+0x133/0x1cd [cachefiles] [] ? cachefiles_lookup_object+0xcf/0x12a [cachefiles] [] ? fscache_lookup_object+0x110/0x122 [fscache] [] ? fscache_object_slow_work_execute+0x590/0x6bc [fscache] [] ? slow_work_thread+0x285/0x43a [] ? autoremove_wake_function+0x0/0x2e [] ? slow_work_thread+0x0/0x43a [] ? kthread+0x54/0x81 [] ? child_rip+0xa/0x20 [] ? kthread+0x0/0x81 [] ? child_rip+0x0/0x20 CacheFiles: I/O Error: Readpage failed on backing file 200000000000810 FS-Cache: Cache cachefiles stopped due to I/O error Reported-by: Christian Kujau Reported-by: Takashi Iwai Reported-by: Duc Le Minh Signed-off-by: David Howells --- fs/cachefiles/rdwr.c | 99 ++++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 93 insertions(+), 6 deletions(-) (limited to 'fs/cachefiles/rdwr.c') diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c index 5a84fd7109a..1d833256386 100644 --- a/fs/cachefiles/rdwr.c +++ b/fs/cachefiles/rdwr.c @@ -40,8 +40,10 @@ static int cachefiles_read_waiter(wait_queue_t *wait, unsigned mode, _debug("--- monitor %p %lx ---", page, page->flags); - if (!PageUptodate(page) && !PageError(page)) - dump_stack(); + if (!PageUptodate(page) && !PageError(page)) { + /* unlocked, not uptodate and not erronous? */ + _debug("page probably truncated"); + } /* remove from the waitqueue */ list_del(&wait->task_list); @@ -60,6 +62,84 @@ static int cachefiles_read_waiter(wait_queue_t *wait, unsigned mode, return 0; } +/* + * handle a probably truncated page + * - check to see if the page is still relevant and reissue the read if + * possible + * - return -EIO on error, -ENODATA if the page is gone, -EINPROGRESS if we + * must wait again and 0 if successful + */ +static int cachefiles_read_reissue(struct cachefiles_object *object, + struct cachefiles_one_read *monitor) +{ + struct address_space *bmapping = object->backer->d_inode->i_mapping; + struct page *backpage = monitor->back_page, *backpage2; + int ret; + + kenter("{ino=%lx},{%lx,%lx}", + object->backer->d_inode->i_ino, + backpage->index, backpage->flags); + + /* skip if the page was truncated away completely */ + if (backpage->mapping != bmapping) { + kleave(" = -ENODATA [mapping]"); + return -ENODATA; + } + + backpage2 = find_get_page(bmapping, backpage->index); + if (!backpage2) { + kleave(" = -ENODATA [gone]"); + return -ENODATA; + } + + if (backpage != backpage2) { + put_page(backpage2); + kleave(" = -ENODATA [different]"); + return -ENODATA; + } + + /* the page is still there and we already have a ref on it, so we don't + * need a second */ + put_page(backpage2); + + INIT_LIST_HEAD(&monitor->op_link); + add_page_wait_queue(backpage, &monitor->monitor); + + if (trylock_page(backpage)) { + ret = -EIO; + if (PageError(backpage)) + goto unlock_discard; + ret = 0; + if (PageUptodate(backpage)) + goto unlock_discard; + + kdebug("reissue read"); + ret = bmapping->a_ops->readpage(NULL, backpage); + if (ret < 0) + goto unlock_discard; + } + + /* but the page may have been read before the monitor was installed, so + * the monitor may miss the event - so we have to ensure that we do get + * one in such a case */ + if (trylock_page(backpage)) { + _debug("jumpstart %p {%lx}", backpage, backpage->flags); + unlock_page(backpage); + } + + /* it'll reappear on the todo list */ + kleave(" = -EINPROGRESS"); + return -EINPROGRESS; + +unlock_discard: + unlock_page(backpage); + spin_lock_irq(&object->work_lock); + list_del(&monitor->op_link); + spin_unlock_irq(&object->work_lock); + kleave(" = %d", ret); + return ret; +} + /* * copy data from backing pages to netfs pages to complete a read operation * - driven by FS-Cache's thread pool @@ -92,20 +172,26 @@ static void cachefiles_read_copier(struct fscache_operation *_op) _debug("- copy {%lu}", monitor->back_page->index); - error = -EIO; + recheck: if (PageUptodate(monitor->back_page)) { copy_highpage(monitor->netfs_page, monitor->back_page); pagevec_add(&pagevec, monitor->netfs_page); fscache_mark_pages_cached(monitor->op, &pagevec); error = 0; - } - - if (error) + } else if (!PageError(monitor->back_page)) { + /* the page has probably been truncated */ + error = cachefiles_read_reissue(object, monitor); + if (error == -EINPROGRESS) + goto next; + goto recheck; + } else { cachefiles_io_error_obj( object, "Readpage failed on backing file %lx", (unsigned long) monitor->back_page->flags); + error = -EIO; + } page_cache_release(monitor->back_page); @@ -114,6 +200,7 @@ static void cachefiles_read_copier(struct fscache_operation *_op) fscache_put_retrieval(op); kfree(monitor); + next: /* let the thread pool have some air occasionally */ max--; if (max < 0 || need_resched()) { -- cgit v1.2.3-70-g09d2 From 3350b2acdd39d23db52710045536b943fe38a35c Mon Sep 17 00:00:00 2001 From: Marc Dionne Date: Tue, 1 Dec 2009 14:09:24 +0000 Subject: CacheFiles: Update IMA counters when using dentry_open When IMA is active, using dentry_open without updating the IMA counters will result in free/open imbalance errors when fput is eventually called. Signed-off-by: Marc Dionne Signed-off-by: David Howells Signed-off-by: Linus Torvalds --- fs/cachefiles/rdwr.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'fs/cachefiles/rdwr.c') diff --git a/fs/cachefiles/rdwr.c b/fs/cachefiles/rdwr.c index 1d833256386..a6c8c6fe8df 100644 --- a/fs/cachefiles/rdwr.c +++ b/fs/cachefiles/rdwr.c @@ -11,6 +11,7 @@ #include #include +#include #include "internal.h" /* @@ -922,6 +923,7 @@ int cachefiles_write_page(struct fscache_storage *op, struct page *page) if (IS_ERR(file)) { ret = PTR_ERR(file); } else { + ima_counts_get(file); ret = -EIO; if (file->f_op->write) { pos = (loff_t) page->index << PAGE_SHIFT; -- cgit v1.2.3-70-g09d2