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author | Pavel Shilovsky <piastryyy@gmail.com> | 2010-12-14 08:50:41 (GMT) |
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committer | Steve French <sfrench@us.ibm.com> | 2011-01-20 21:42:29 (GMT) |
commit | a70307eeeb25b89f6b2baf3cf3f0cef83c96ba12 (patch) | |
tree | f96abbc5d22884fd4c15fdc834c769b7fcf790c4 /fs/cifs/file.c | |
parent | 7a6a19b17ab9103ec708c18befd28f2a3908d4c1 (diff) | |
download | linux-fsl-qoriq-a70307eeeb25b89f6b2baf3cf3f0cef83c96ba12.tar.xz |
CIFS: Implement cifs_strict_readv (try #4)
Read from the cache if we have at least Level II oplock - otherwise
read from the server. Add cifs_user_readv to let the client read into
iovec buffers.
Reviewed-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Diffstat (limited to 'fs/cifs/file.c')
-rw-r--r-- | fs/cifs/file.c | 116 |
1 files changed, 79 insertions, 37 deletions
diff --git a/fs/cifs/file.c b/fs/cifs/file.c index 0b32377..d7d65a7 100644 --- a/fs/cifs/file.c +++ b/fs/cifs/file.c @@ -1619,42 +1619,42 @@ int cifs_flush(struct file *file, fl_owner_t id) return rc; } -ssize_t cifs_user_read(struct file *file, char __user *read_data, - size_t read_size, loff_t *poffset) +static ssize_t +cifs_iovec_read(struct file *file, const struct iovec *iov, + unsigned long nr_segs, loff_t *poffset) { - int rc = -EACCES; - unsigned int bytes_read = 0; - unsigned int total_read = 0; - unsigned int current_read_size; + int rc; + int xid; + unsigned int total_read, bytes_read = 0; + size_t len, cur_len; + int iov_offset = 0; struct cifs_sb_info *cifs_sb; struct cifsTconInfo *pTcon; - int xid; struct cifsFileInfo *open_file; - char *smb_read_data; - char __user *current_offset; struct smb_com_read_rsp *pSMBr; + char *read_data; + + if (!nr_segs) + return 0; + + len = iov_length(iov, nr_segs); + if (!len) + return 0; xid = GetXid(); cifs_sb = CIFS_SB(file->f_path.dentry->d_sb); - if (file->private_data == NULL) { - rc = -EBADF; - FreeXid(xid); - return rc; - } open_file = file->private_data; pTcon = tlink_tcon(open_file->tlink); if ((file->f_flags & O_ACCMODE) == O_WRONLY) cFYI(1, "attempting read on write only file instance"); - for (total_read = 0, current_offset = read_data; - read_size > total_read; - total_read += bytes_read, current_offset += bytes_read) { - current_read_size = min_t(const int, read_size - total_read, - cifs_sb->rsize); + for (total_read = 0; total_read < len; total_read += bytes_read) { + cur_len = min_t(const size_t, len - total_read, cifs_sb->rsize); rc = -EAGAIN; - smb_read_data = NULL; + read_data = NULL; + while (rc == -EAGAIN) { int buf_type = CIFS_NO_BUFFER; if (open_file->invalidHandle) { @@ -1662,27 +1662,25 @@ ssize_t cifs_user_read(struct file *file, char __user *read_data, if (rc != 0) break; } - rc = CIFSSMBRead(xid, pTcon, - open_file->netfid, - current_read_size, *poffset, - &bytes_read, &smb_read_data, - &buf_type); - pSMBr = (struct smb_com_read_rsp *)smb_read_data; - if (smb_read_data) { - if (copy_to_user(current_offset, - smb_read_data + - 4 /* RFC1001 length field */ + - le16_to_cpu(pSMBr->DataOffset), - bytes_read)) + rc = CIFSSMBRead(xid, pTcon, open_file->netfid, + cur_len, *poffset, &bytes_read, + &read_data, &buf_type); + pSMBr = (struct smb_com_read_rsp *)read_data; + if (read_data) { + char *data_offset = read_data + 4 + + le16_to_cpu(pSMBr->DataOffset); + if (memcpy_toiovecend(iov, data_offset, + iov_offset, bytes_read)) rc = -EFAULT; - if (buf_type == CIFS_SMALL_BUFFER) - cifs_small_buf_release(smb_read_data); + cifs_small_buf_release(read_data); else if (buf_type == CIFS_LARGE_BUFFER) - cifs_buf_release(smb_read_data); - smb_read_data = NULL; + cifs_buf_release(read_data); + read_data = NULL; + iov_offset += bytes_read; } } + if (rc || (bytes_read == 0)) { if (total_read) { break; @@ -1695,13 +1693,57 @@ ssize_t cifs_user_read(struct file *file, char __user *read_data, *poffset += bytes_read; } } + FreeXid(xid); return total_read; } +ssize_t cifs_user_read(struct file *file, char __user *read_data, + size_t read_size, loff_t *poffset) +{ + struct iovec iov; + iov.iov_base = read_data; + iov.iov_len = read_size; + + return cifs_iovec_read(file, &iov, 1, poffset); +} + +static ssize_t cifs_user_readv(struct kiocb *iocb, const struct iovec *iov, + unsigned long nr_segs, loff_t pos) +{ + ssize_t read; + + read = cifs_iovec_read(iocb->ki_filp, iov, nr_segs, &pos); + if (read > 0) + iocb->ki_pos = pos; + + return read; +} + +ssize_t cifs_strict_readv(struct kiocb *iocb, const struct iovec *iov, + unsigned long nr_segs, loff_t pos) +{ + struct inode *inode; + + inode = iocb->ki_filp->f_path.dentry->d_inode; + + 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. + */ + + return cifs_user_readv(iocb, iov, nr_segs, pos); +} static ssize_t cifs_read(struct file *file, char *read_data, size_t read_size, - loff_t *poffset) + loff_t *poffset) { int rc = -EACCES; unsigned int bytes_read = 0; |