diff options
author | Sage Weil <sage@newdream.net> | 2010-02-09 14:04:02 -0800 |
---|---|---|
committer | Sage Weil <sage@newdream.net> | 2010-02-11 11:48:53 -0800 |
commit | 6a026589ba333185c466c906376fe022a27a53f9 (patch) | |
tree | 7c536163e2192928978b79d5a6bbd79dd5993777 /fs/ceph | |
parent | 68c283236a1e0772e1a469dd2ffc17afc300b07b (diff) |
ceph: fix sync read eof check deadlock
If a sync read gets a short result from the OSD, it may need to do a
getattr to see if it is short due to reaching end-of-file. The getattr
was being done while holding a reference to FILE_RD, which can lead to
a deadlock if the MDS is revoking that capability bit and can't process
the getattr until it does.
We fix this by setting a flag if EOF size validation is needed, and doing
the getattr in ceph_aio_read, after the RD cap ref is dropped. If the
read needs to be continued, we loop and continue traversing the file.
Signed-off-by: Sage Weil <sage@newdream.net>
Diffstat (limited to 'fs/ceph')
-rw-r--r-- | fs/ceph/file.c | 39 |
1 files changed, 26 insertions, 13 deletions
diff --git a/fs/ceph/file.c b/fs/ceph/file.c index bbf1ccf2d56..2c4ae4441ca 100644 --- a/fs/ceph/file.c +++ b/fs/ceph/file.c @@ -431,7 +431,8 @@ static void zero_page_vector_range(int off, int len, struct page **pages) */ static int striped_read(struct inode *inode, u64 off, u64 len, - struct page **pages, int num_pages) + struct page **pages, int num_pages, + int *checkeof) { struct ceph_client *client = ceph_inode_to_client(inode); struct ceph_inode_info *ci = ceph_inode(inode); @@ -497,15 +498,7 @@ more: } /* check i_size */ - ret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE); - if (ret < 0) - goto out; - - /* hit EOF? */ - if (pos >= inode->i_size) - goto out; - - goto more; + *checkeof = 1; } out: @@ -522,7 +515,7 @@ out: * If the read spans object boundary, just do multiple reads. */ static ssize_t ceph_sync_read(struct file *file, char __user *data, - unsigned len, loff_t *poff) + unsigned len, loff_t *poff, int *checkeof) { struct inode *inode = file->f_dentry->d_inode; struct page **pages; @@ -552,7 +545,7 @@ static ssize_t ceph_sync_read(struct file *file, char __user *data, if (ret < 0) goto done; - ret = striped_read(inode, off, len, pages, num_pages); + ret = striped_read(inode, off, len, pages, num_pages, checkeof); if (ret >= 0 && (file->f_flags & O_DIRECT) == 0) ret = copy_page_vector_to_user(pages, data, off, ret); @@ -746,11 +739,14 @@ static ssize_t ceph_aio_read(struct kiocb *iocb, const struct iovec *iov, size_t len = iov->iov_len; struct inode *inode = filp->f_dentry->d_inode; struct ceph_inode_info *ci = ceph_inode(inode); + void *base = iov->iov_base; ssize_t ret; int got = 0; + int checkeof = 0, read = 0; dout("aio_read %p %llx.%llx %llu~%u trying to get caps on %p\n", inode, ceph_vinop(inode), pos, (unsigned)len, inode); +again: __ceph_do_pending_vmtruncate(inode); ret = ceph_get_caps(ci, CEPH_CAP_FILE_RD, CEPH_CAP_FILE_CACHE, &got, -1); @@ -764,7 +760,7 @@ static ssize_t ceph_aio_read(struct kiocb *iocb, const struct iovec *iov, (iocb->ki_filp->f_flags & O_DIRECT) || (inode->i_sb->s_flags & MS_SYNCHRONOUS)) /* hmm, this isn't really async... */ - ret = ceph_sync_read(filp, iov->iov_base, len, ppos); + ret = ceph_sync_read(filp, base, len, ppos, &checkeof); else ret = generic_file_aio_read(iocb, iov, nr_segs, pos); @@ -772,6 +768,23 @@ out: dout("aio_read %p %llx.%llx dropping cap refs on %s = %d\n", inode, ceph_vinop(inode), ceph_cap_string(got), (int)ret); ceph_put_cap_refs(ci, got); + + if (checkeof && ret >= 0) { + int statret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE); + + /* hit EOF or hole? */ + if (statret == 0 && *ppos < inode->i_size) { + dout("aio_read sync_read hit hole, reading more\n"); + read += ret; + base += ret; + len -= ret; + checkeof = 0; + goto again; + } + } + if (ret >= 0) + ret += read; + return ret; } |