From 46b59b2be05a71d80d76883d2f495f182d768f47 Mon Sep 17 00:00:00 2001 From: "Yan, Zheng" Date: Wed, 18 May 2016 15:25:03 +0800 Subject: ceph: disable fscache when inode is opened for write All other filesystems do not add dirty pages to fscache. They all disable fscache when inode is opened for write. Only ceph adds dirty pages to fscache, but the code is buggy. Signed-off-by: Yan, Zheng --- fs/ceph/cache.c | 54 ++++++++++++++++++++++++++++++++++++++---------------- 1 file changed, 38 insertions(+), 16 deletions(-) (limited to 'fs/ceph/cache.c') diff --git a/fs/ceph/cache.c b/fs/ceph/cache.c index c052b5bf219b..c19db6afd0cc 100644 --- a/fs/ceph/cache.c +++ b/fs/ceph/cache.c @@ -181,32 +181,26 @@ static const struct fscache_cookie_def ceph_fscache_inode_object_def = { .now_uncached = ceph_fscache_inode_now_uncached, }; -void ceph_fscache_register_inode_cookie(struct ceph_fs_client* fsc, - struct ceph_inode_info* ci) +void ceph_fscache_register_inode_cookie(struct inode *inode) { - struct inode* inode = &ci->vfs_inode; + struct ceph_inode_info *ci = ceph_inode(inode); + struct ceph_fs_client *fsc = ceph_inode_to_client(inode); /* No caching for filesystem */ if (fsc->fscache == NULL) return; /* Only cache for regular files that are read only */ - if ((ci->vfs_inode.i_mode & S_IFREG) == 0) + if (!S_ISREG(inode->i_mode)) return; - /* Avoid multiple racing open requests */ - inode_lock(inode); - - if (ci->fscache) - goto done; - - ci->fscache = fscache_acquire_cookie(fsc->fscache, - &ceph_fscache_inode_object_def, - ci, true); - fscache_check_consistency(ci->fscache); -done: + inode_lock_nested(inode, I_MUTEX_CHILD); + if (!ci->fscache) { + ci->fscache = fscache_acquire_cookie(fsc->fscache, + &ceph_fscache_inode_object_def, + ci, false); + } inode_unlock(inode); - } void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci) @@ -222,6 +216,34 @@ void ceph_fscache_unregister_inode_cookie(struct ceph_inode_info* ci) fscache_relinquish_cookie(cookie, 0); } +static bool ceph_fscache_can_enable(void *data) +{ + struct inode *inode = data; + return !inode_is_open_for_write(inode); +} + +void ceph_fscache_file_set_cookie(struct inode *inode, struct file *filp) +{ + struct ceph_inode_info *ci = ceph_inode(inode); + + if (!fscache_cookie_valid(ci->fscache)) + return; + + if (inode_is_open_for_write(inode)) { + dout("fscache_file_set_cookie %p %p disabling cache\n", + inode, filp); + fscache_disable_cookie(ci->fscache, false); + fscache_uncache_all_inode_pages(ci->fscache, inode); + } else { + fscache_enable_cookie(ci->fscache, ceph_fscache_can_enable, + inode); + if (fscache_cookie_enabled(ci->fscache)) { + dout("fscache_file_set_cookie %p %p enabing cache\n", + inode, filp); + } + } +} + static void ceph_vfs_readpage_complete(struct page *page, void *data, int error) { if (!error) -- cgit v1.2.3 From f7f7e7a0635dedd5064fba255cb3facfa87b06d6 Mon Sep 17 00:00:00 2001 From: "Yan, Zheng" Date: Wed, 18 May 2016 20:31:55 +0800 Subject: ceph: improve fscache revalidation There are several issues in fscache revalidation code. - In ceph_revalidate_work(), fscache_invalidate() is called when fscache_check_consistency() return 0. This is complete wrong because 0 means cache is valid. - Handle_cap_grant() calls ceph_queue_revalidate() if client already has CAP_FILE_CACHE. This code is confusing. Client should revalidate the cache each time it got CAP_FILE_CACHE anew. - In Handle_cap_grant(), fscache_invalidate() is called if MDS revokes CAP_FILE_CACHE. This is inconsistency with the case that inode get evicted. In the later case, the cache is not discarded. Client may use the cache when inode is reloaded. This patch moves the fscache revalidation into ceph_get_caps(). Client revalidates the cache after it gets CAP_FILE_CACHE. i_rdcache_gen should keep constance while CAP_FILE_CACHE is used. If i_fscache_gen is not equal to i_rdcache_gen, client needs to check cache's consistency. Signed-off-by: Yan, Zheng --- fs/ceph/cache.c | 84 ++++++++++++--------------------------------------------- 1 file changed, 17 insertions(+), 67 deletions(-) (limited to 'fs/ceph/cache.c') diff --git a/fs/ceph/cache.c b/fs/ceph/cache.c index c19db6afd0cc..5b3f4828f214 100644 --- a/fs/ceph/cache.c +++ b/fs/ceph/cache.c @@ -69,15 +69,8 @@ int ceph_fscache_register_fs(struct ceph_fs_client* fsc) fsc->fscache = fscache_acquire_cookie(ceph_cache_netfs.primary_index, &ceph_fscache_fsid_object_def, fsc, true); - - if (fsc->fscache == NULL) { + if (!fsc->fscache) pr_err("Unable to resgister fsid: %p fscache cookie", fsc); - return 0; - } - - fsc->revalidate_wq = alloc_workqueue("ceph-revalidate", 0, 1); - if (fsc->revalidate_wq == NULL) - return -ENOMEM; return 0; } @@ -260,8 +253,7 @@ static void ceph_vfs_readpage_complete_unlock(struct page *page, void *data, int static inline bool cache_valid(struct ceph_inode_info *ci) { - return ((ceph_caps_issued(ci) & CEPH_CAP_FILE_CACHE) && - (ci->i_fscache_gen == ci->i_rdcache_gen)); + return ci->i_fscache_gen == ci->i_rdcache_gen; } @@ -354,69 +346,27 @@ void ceph_invalidate_fscache_page(struct inode* inode, struct page *page) void ceph_fscache_unregister_fs(struct ceph_fs_client* fsc) { - if (fsc->revalidate_wq) - destroy_workqueue(fsc->revalidate_wq); - fscache_relinquish_cookie(fsc->fscache, 0); fsc->fscache = NULL; } -static void ceph_revalidate_work(struct work_struct *work) -{ - int issued; - u32 orig_gen; - struct ceph_inode_info *ci = container_of(work, struct ceph_inode_info, - i_revalidate_work); - struct inode *inode = &ci->vfs_inode; - - spin_lock(&ci->i_ceph_lock); - issued = __ceph_caps_issued(ci, NULL); - orig_gen = ci->i_rdcache_gen; - spin_unlock(&ci->i_ceph_lock); - - if (!(issued & CEPH_CAP_FILE_CACHE)) { - dout("revalidate_work lost cache before validation %p\n", - inode); - goto out; - } - - if (!fscache_check_consistency(ci->fscache)) - fscache_invalidate(ci->fscache); - - spin_lock(&ci->i_ceph_lock); - /* Update the new valid generation (backwards sanity check too) */ - if (orig_gen > ci->i_fscache_gen) { - ci->i_fscache_gen = orig_gen; - } - spin_unlock(&ci->i_ceph_lock); - -out: - iput(&ci->vfs_inode); -} - -void ceph_queue_revalidate(struct inode *inode) +/* + * caller should hold CEPH_CAP_FILE_{RD,CACHE} + */ +void ceph_fscache_revalidate_cookie(struct ceph_inode_info *ci) { - struct ceph_fs_client *fsc = ceph_sb_to_client(inode->i_sb); - struct ceph_inode_info *ci = ceph_inode(inode); - - if (fsc->revalidate_wq == NULL || ci->fscache == NULL) + if (cache_valid(ci)) return; - ihold(inode); - - if (queue_work(ceph_sb_to_client(inode->i_sb)->revalidate_wq, - &ci->i_revalidate_work)) { - dout("ceph_queue_revalidate %p\n", inode); - } else { - dout("ceph_queue_revalidate %p failed\n)", inode); - iput(inode); + /* resue i_truncate_mutex. There should be no pending + * truncate while the caller holds CEPH_CAP_FILE_RD */ + mutex_lock(&ci->i_truncate_mutex); + if (!cache_valid(ci)) { + if (fscache_check_consistency(ci->fscache)) + fscache_invalidate(ci->fscache); + spin_lock(&ci->i_ceph_lock); + ci->i_fscache_gen = ci->i_rdcache_gen; + spin_unlock(&ci->i_ceph_lock); } -} - -void ceph_fscache_inode_init(struct ceph_inode_info *ci) -{ - ci->fscache = NULL; - /* The first load is verifed cookie open time */ - ci->i_fscache_gen = 1; - INIT_WORK(&ci->i_revalidate_work, ceph_revalidate_work); + mutex_unlock(&ci->i_truncate_mutex); } -- cgit v1.2.3 From f6973c09490c919398fc87d9c6bec9c0b670c4c4 Mon Sep 17 00:00:00 2001 From: "Yan, Zheng" Date: Fri, 20 May 2016 16:57:29 +0800 Subject: ceph: use i_version to check validity of fscache Signed-off-by: Yan, Zheng --- fs/ceph/cache.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'fs/ceph/cache.c') diff --git a/fs/ceph/cache.c b/fs/ceph/cache.c index 5b3f4828f214..238c55b01723 100644 --- a/fs/ceph/cache.c +++ b/fs/ceph/cache.c @@ -25,6 +25,7 @@ #include "cache.h" struct ceph_aux_inode { + u64 version; struct timespec mtime; loff_t size; }; @@ -98,6 +99,7 @@ static uint16_t ceph_fscache_inode_get_aux(const void *cookie_netfs_data, const struct inode* inode = &ci->vfs_inode; memset(&aux, 0, sizeof(aux)); + aux.version = ci->i_version; aux.mtime = inode->i_mtime; aux.size = i_size_read(inode); @@ -124,6 +126,7 @@ static enum fscache_checkaux ceph_fscache_inode_check_aux( return FSCACHE_CHECKAUX_OBSOLETE; memset(&aux, 0, sizeof(aux)); + aux.version = ci->i_version; aux.mtime = inode->i_mtime; aux.size = i_size_read(inode); -- cgit v1.2.3