Read from the cache if we have at least Level II oplock - otherwise read from the server.
Signed-off-by: Pavel Shilovsky <[email protected]> --- fs/cifs/cifsfs.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++-- fs/cifs/cifsproto.h | 2 ++ fs/cifs/file.c | 4 ++-- 3 files changed, 52 insertions(+), 4 deletions(-) diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c index a0e35d3..e3f0024 100644 --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -575,8 +575,54 @@ cifs_do_mount(struct file_system_type *fs_type, static ssize_t cifs_strict_read(struct kiocb *iocb, const struct iovec *iov, unsigned long nr_segs, loff_t pos) { - ssize_t read = 0; - /* BB */ + struct inode *inode; + struct cifs_sb_info *cifs_sb; + ssize_t read; + unsigned long i, len = 0; + char *buf, *offset; + + inode = iocb->ki_filp->f_path.dentry->d_inode; + cifs_sb = CIFS_SB(iocb->ki_filp->f_path.dentry->d_sb); + + if (CIFS_I(inode)->clientCanCacheRead) + return generic_file_aio_read(iocb, iov, nr_segs, pos); + + /* + * In strict cache mode we need to read from the server all the time + * if we don't have level II oplock because the server can delay mtime + * change - so we can't make a decision about inode invalidating. + * And we can also fail with pagereading if there are mandatory locks + * on pages affected by this read but not on the region from pos to + * pos+len-1. + */ + + for (i = 0; i < nr_segs; i++) + len += iov[i].iov_len; + + buf = kmalloc(len, GFP_KERNEL); + + read = cifs_read(iocb->ki_filp, buf, len, &pos); + if (read < 0) { + kfree(buf); + return read; + } + + for (i = 0, offset = buf, len = read; i < nr_segs && len; i++) { + unsigned long cur_len = min_t(unsigned long, len, + iov[i].iov_len); + + if (copy_to_user(iov[i].iov_base, offset, cur_len)) { + kfree(buf); + return -EFAULT; + } + + len -= cur_len; + offset += cur_len; + } + + iocb->ki_pos = pos; + + kfree(buf); return read; } diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h index e6d1481..05f6446 100644 --- a/fs/cifs/cifsproto.h +++ b/fs/cifs/cifsproto.h @@ -79,6 +79,8 @@ extern int checkSMB(struct smb_hdr *smb, __u16 mid, unsigned int length); extern bool is_valid_oplock_break(struct smb_hdr *smb, struct TCP_Server_Info *); extern bool is_size_safe_to_change(struct cifsInodeInfo *, __u64 eof); +extern ssize_t cifs_read(struct file *file, char *read_data, size_t read_size, + loff_t *poffset); extern struct cifsFileInfo *find_writable_file(struct cifsInodeInfo *, bool); extern struct cifsFileInfo *find_readable_file(struct cifsInodeInfo *, bool); extern unsigned int smbCalcSize(struct smb_hdr *ptr); diff --git a/fs/cifs/file.c b/fs/cifs/file.c index dd1e59a..1f96326 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -1758,8 +1758,8 @@ ssize_t cifs_user_read(struct file *file, char __user *read_data, } -static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size, - loff_t *poffset) +ssize_t cifs_read(struct file *file, char *read_data, size_t read_size, + loff_t *poffset) { int rc = -EACCES; unsigned int bytes_read = 0; -- 1.7.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
