diff options
Diffstat (limited to 'fs/gfs2/jdata.c')
| -rw-r--r-- | fs/gfs2/jdata.c | 382 |
1 files changed, 382 insertions, 0 deletions
diff --git a/fs/gfs2/jdata.c b/fs/gfs2/jdata.c new file mode 100644 index 0000000..d4adbf1 --- /dev/null +++ b/fs/gfs2/jdata.c @@ -0,0 +1,382 @@ +/* + * Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved. + * Copyright (C) 2004-2005 Red Hat, Inc. All rights reserved. + * + * This copyrighted material is made available to anyone wishing to use, + * modify, copy, or redistribute it subject to the terms and conditions + * of the GNU General Public License v.2. + */ + +#include <linux/sched.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/completion.h> +#include <linux/buffer_head.h> +#include <asm/semaphore.h> +#include <asm/uaccess.h> + +#include "gfs2.h" +#include "bmap.h" +#include "inode.h" +#include "jdata.h" +#include "meta_io.h" +#include "trans.h" + +int gfs2_jdata_get_buffer(struct gfs2_inode *ip, uint64_t block, int new, + struct buffer_head **bhp) +{ + struct buffer_head *bh; + int error = 0; + + if (new) { + bh = gfs2_meta_new(ip->i_gl, block); + gfs2_trans_add_bh(ip->i_gl, bh); + gfs2_metatype_set(bh, GFS2_METATYPE_JD, GFS2_FORMAT_JD); + gfs2_buffer_clear_tail(bh, sizeof(struct gfs2_meta_header)); + } else { + error = gfs2_meta_read(ip->i_gl, block, + DIO_START | DIO_WAIT, &bh); + if (error) + return error; + if (gfs2_metatype_check(ip->i_sbd, bh, GFS2_METATYPE_JD)) { + brelse(bh); + return -EIO; + } + } + + *bhp = bh; + + return 0; +} + +/** + * gfs2_copy2mem - Trivial copy function for gfs2_jdata_read() + * @bh: The buffer to copy from, or NULL meaning zero the buffer + * @buf: The buffer to copy/zero + * @offset: The offset in the buffer to copy from + * @size: The amount of data to copy/zero + * + * Returns: errno + */ + +int gfs2_copy2mem(struct buffer_head *bh, char **buf, unsigned int offset, + unsigned int size) +{ + if (bh) + memcpy(*buf, bh->b_data + offset, size); + else + memset(*buf, 0, size); + *buf += size; + return 0; +} + +/** + * gfs2_copy2user - Copy bytes to user space for gfs2_jdata_read() + * @bh: The buffer + * @buf: The destination of the data + * @offset: The offset into the buffer + * @size: The amount of data to copy + * + * Returns: errno + */ + +int gfs2_copy2user(struct buffer_head *bh, char **buf, unsigned int offset, + unsigned int size) +{ + int error; + + if (bh) + error = copy_to_user(*buf, bh->b_data + offset, size); + else + error = clear_user(*buf, size); + + if (error) + error = -EFAULT; + else + *buf += size; + + return error; +} + +static int jdata_read_stuffed(struct gfs2_inode *ip, char *buf, + unsigned int offset, unsigned int size, + read_copy_fn_t copy_fn) +{ + struct buffer_head *dibh; + int error; + + error = gfs2_meta_inode_buffer(ip, &dibh); + if (!error) { + error = copy_fn(dibh, &buf, + offset + sizeof(struct gfs2_dinode), size); + brelse(dibh); + } + + return (error) ? error : size; +} + +/** + * gfs2_jdata_read - Read a jdata file + * @ip: The GFS2 Inode + * @buf: The buffer to place result into + * @offset: File offset to begin jdata_readng from + * @size: Amount of data to transfer + * @copy_fn: Function to actually perform the copy + * + * The @copy_fn only copies a maximum of a single block at once so + * we are safe calling it with int arguments. It is done so that + * we don't needlessly put 64bit arguments on the stack and it + * also makes the code in the @copy_fn nicer too. + * + * Returns: The amount of data actually copied or the error + */ + +int gfs2_jdata_read(struct gfs2_inode *ip, char __user *buf, uint64_t offset, + unsigned int size, read_copy_fn_t copy_fn) +{ + struct gfs2_sbd *sdp = ip->i_sbd; + uint64_t lblock, dblock; + uint32_t extlen = 0; + unsigned int o; + int copied = 0; + int error = 0; + + if (offset >= ip->i_di.di_size) + return 0; + + if ((offset + size) > ip->i_di.di_size) + size = ip->i_di.di_size - offset; + + if (!size) + return 0; + + if (gfs2_is_stuffed(ip)) + return jdata_read_stuffed(ip, buf, (unsigned int)offset, size, + copy_fn); + + if (gfs2_assert_warn(sdp, gfs2_is_jdata(ip))) + return -EINVAL; + + lblock = offset; + o = do_div(lblock, sdp->sd_jbsize) + + sizeof(struct gfs2_meta_header); + + while (copied < size) { + unsigned int amount; + struct buffer_head *bh; + int new; + + amount = size - copied; + if (amount > sdp->sd_sb.sb_bsize - o) + amount = sdp->sd_sb.sb_bsize - o; + + if (!extlen) { + new = 0; + error = gfs2_block_map(ip, lblock, &new, + &dblock, &extlen); + if (error) + goto fail; + } + + if (extlen > 1) + gfs2_meta_ra(ip->i_gl, dblock, extlen); + + if (dblock) { + error = gfs2_jdata_get_buffer(ip, dblock, new, &bh); + if (error) + goto fail; + dblock++; + extlen--; + } else + bh = NULL; + + error = copy_fn(bh, &buf, o, amount); + brelse(bh); + if (error) + goto fail; + + copied += amount; + lblock++; + + o = sizeof(struct gfs2_meta_header); + } + + return copied; + + fail: + return (copied) ? copied : error; +} + +/** + * gfs2_copy_from_mem - Trivial copy function for gfs2_jdata_write() + * @bh: The buffer to copy to or clear + * @buf: The buffer to copy from + * @offset: The offset in the buffer to write to + * @size: The amount of data to write + * + * Returns: errno + */ + +int gfs2_copy_from_mem(struct gfs2_inode *ip, struct buffer_head *bh, + const char **buf, unsigned int offset, unsigned int size) +{ + gfs2_trans_add_bh(ip->i_gl, bh); + memcpy(bh->b_data + offset, *buf, size); + + *buf += size; + + return 0; +} + +/** + * gfs2_copy_from_user - Copy bytes from user space for gfs2_jdata_write() + * @bh: The buffer to copy to or clear + * @buf: The buffer to copy from + * @offset: The offset in the buffer to write to + * @size: The amount of data to write + * + * Returns: errno + */ + +int gfs2_copy_from_user(struct gfs2_inode *ip, struct buffer_head *bh, + const char __user **buf, unsigned int offset, unsigned int size) +{ + int error = 0; + + gfs2_trans_add_bh(ip->i_gl, bh); + if (copy_from_user(bh->b_data + offset, *buf, size)) + error = -EFAULT; + else + *buf += size; + + return error; +} + +static int jdata_write_stuffed(struct gfs2_inode *ip, char *buf, + unsigned int offset, unsigned int size, + write_copy_fn_t copy_fn) +{ + struct buffer_head *dibh; + int error; + + error = gfs2_meta_inode_buffer(ip, &dibh); + if (error) + return error; + + error = copy_fn(ip, + dibh, &buf, + offset + sizeof(struct gfs2_dinode), size); + if (!error) { + if (ip->i_di.di_size < offset + size) + ip->i_di.di_size = offset + size; + ip->i_di.di_mtime = ip->i_di.di_ctime = get_seconds(); + gfs2_dinode_out(&ip->i_di, dibh->b_data); + } + + brelse(dibh); + + return (error) ? error : size; +} + +/** + * gfs2_jdata_write - Write bytes to a file + * @ip: The GFS2 inode + * @buf: The buffer containing information to be written + * @offset: The file offset to start writing at + * @size: The amount of data to write + * @copy_fn: Function to do the actual copying + * + * Returns: The number of bytes correctly written or error code + */ + +int gfs2_jdata_write(struct gfs2_inode *ip, const char __user *buf, uint64_t offset, + unsigned int size, write_copy_fn_t copy_fn) +{ + struct gfs2_sbd *sdp = ip->i_sbd; + struct buffer_head *dibh; + uint64_t lblock, dblock; + uint32_t extlen = 0; + unsigned int o; + int copied = 0; + int error = 0; + + if (!size) + return 0; + + if (gfs2_is_stuffed(ip) && + offset + size <= sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) + return jdata_write_stuffed(ip, buf, (unsigned int)offset, size, + copy_fn); + + if (gfs2_assert_warn(sdp, gfs2_is_jdata(ip))) + return -EINVAL; + + if (gfs2_is_stuffed(ip)) { + error = gfs2_unstuff_dinode(ip, NULL, NULL); + if (error) + return error; + } + + lblock = offset; + o = do_div(lblock, sdp->sd_jbsize) + sizeof(struct gfs2_meta_header); + + while (copied < size) { + unsigned int amount; + struct buffer_head *bh; + int new; + + amount = size - copied; + if (amount > sdp->sd_sb.sb_bsize - o) + amount = sdp->sd_sb.sb_bsize - o; + + if (!extlen) { + new = 1; + error = gfs2_block_map(ip, lblock, &new, + &dblock, &extlen); + if (error) + goto fail; + error = -EIO; + if (gfs2_assert_withdraw(sdp, dblock)) + goto fail; + } + + error = gfs2_jdata_get_buffer(ip, dblock, + (amount == sdp->sd_jbsize) ? 1 : new, + &bh); + if (error) + goto fail; + + error = copy_fn(ip, bh, &buf, o, amount); + brelse(bh); + if (error) + goto fail; + + copied += amount; + lblock++; + dblock++; + extlen--; + + o = sizeof(struct gfs2_meta_header); + } + + out: + error = gfs2_meta_inode_buffer(ip, &dibh); + if (error) + return error; + + if (ip->i_di.di_size < offset + copied) + ip->i_di.di_size = offset + copied; + ip->i_di.di_mtime = ip->i_di.di_ctime = get_seconds(); + + gfs2_trans_add_bh(ip->i_gl, dibh); + gfs2_dinode_out(&ip->i_di, dibh->b_data); + brelse(dibh); + + return copied; + + fail: + if (copied) + goto out; + return error; +} + |
