Commit 30460e1e authored by Carlos Maiolino's avatar Carlos Maiolino Committed by Al Viro
Browse files

fs: Enable bmap() function to properly return errors



By now, bmap() will either return the physical block number related to
the requested file offset or 0 in case of error or the requested offset
maps into a hole.
This patch makes the needed changes to enable bmap() to proper return
errors, using the return value as an error return, and now, a pointer
must be passed to bmap() to be filled with the mapped physical block.

It will change the behavior of bmap() on return:

- negative value in case of error
- zero on success or map fell into a hole

In case of a hole, the *block will be zero too

Since this is a prep patch, by now, the only error return is -EINVAL if
->bmap doesn't exist.

Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarCarlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent c79f46a2
......@@ -364,7 +364,7 @@ static int read_page(struct file *file, unsigned long index,
int ret = 0;
struct inode *inode = file_inode(file);
struct buffer_head *bh;
sector_t block;
sector_t block, blk_cur;
pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
(unsigned long long)index << PAGE_SHIFT);
......@@ -375,17 +375,21 @@ static int read_page(struct file *file, unsigned long index,
goto out;
}
attach_page_buffers(page, bh);
block = index << (PAGE_SHIFT - inode->i_blkbits);
blk_cur = index << (PAGE_SHIFT - inode->i_blkbits);
while (bh) {
block = blk_cur;
if (count == 0)
bh->b_blocknr = 0;
else {
bh->b_blocknr = bmap(inode, block);
if (bh->b_blocknr == 0) {
/* Cannot use this file! */
ret = bmap(inode, &block);
if (ret || !block) {
ret = -EINVAL;
bh->b_blocknr = 0;
goto out;
}
bh->b_blocknr = block;
bh->b_bdev = inode->i_sb->s_bdev;
if (count < (1<<inode->i_blkbits))
count = 0;
......@@ -399,7 +403,7 @@ static int read_page(struct file *file, unsigned long index,
set_buffer_mapped(bh);
submit_bh(REQ_OP_READ, 0, bh);
}
block++;
blk_cur++;
bh = bh->b_this_page;
}
page->index = index;
......
......@@ -3170,12 +3170,16 @@ static int check_swap_activate(struct file *swap_file, unsigned int max)
while ((probe_block + blocks_per_page) <= last_block && page_no < max) {
unsigned block_in_page;
sector_t first_block;
sector_t block = 0;
int err = 0;
cond_resched();
first_block = bmap(inode, probe_block);
if (first_block == 0)
block = probe_block;
err = bmap(inode, &block);
if (err || !block)
goto bad_bmap;
first_block = block;
/*
* It must be PAGE_SIZE aligned on-disk
......@@ -3187,11 +3191,13 @@ static int check_swap_activate(struct file *swap_file, unsigned int max)
for (block_in_page = 1; block_in_page < blocks_per_page;
block_in_page++) {
sector_t block;
block = bmap(inode, probe_block + block_in_page);
if (block == 0)
block = probe_block + block_in_page;
err = bmap(inode, &block);
if (err || !block)
goto bad_bmap;
if (block != first_block + block_in_page) {
/* Discontiguity */
probe_block++;
......
......@@ -1598,25 +1598,31 @@ retry:
}
EXPORT_SYMBOL(iput);
#ifdef CONFIG_BLOCK
/**
* bmap - find a block number in a file
* @inode: inode of file
* @block: block to find
*
* Returns the block number on the device holding the inode that
* is the disk block number for the block of the file requested.
* That is, asked for block 4 of inode 1 the function will return the
* disk block relative to the disk start that holds that block of the
* file.
* @inode: inode owning the block number being requested
* @block: pointer containing the block to find
*
* Replaces the value in *block with the block number on the device holding
* corresponding to the requested block number in the file.
* That is, asked for block 4 of inode 1 the function will replace the
* 4 in *block, with disk block relative to the disk start that holds that
* block of the file.
*
* Returns -EINVAL in case of error, 0 otherwise. If mapping falls into a
* hole, returns 0 and *block is also set to 0.
*/
sector_t bmap(struct inode *inode, sector_t block)
int bmap(struct inode *inode, sector_t *block)
{
sector_t res = 0;
if (inode->i_mapping->a_ops->bmap)
res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block);
return res;
if (!inode->i_mapping->a_ops->bmap)
return -EINVAL;
*block = inode->i_mapping->a_ops->bmap(inode->i_mapping, *block);
return 0;
}
EXPORT_SYMBOL(bmap);
#endif
/*
* With relative atime, only update atime if the previous atime is
......
......@@ -795,18 +795,23 @@ int jbd2_journal_bmap(journal_t *journal, unsigned long blocknr,
{
int err = 0;
unsigned long long ret;
sector_t block = 0;
if (journal->j_inode) {
ret = bmap(journal->j_inode, blocknr);
if (ret)
*retp = ret;
else {
block = blocknr;
ret = bmap(journal->j_inode, &block);
if (ret || !block) {
printk(KERN_ALERT "%s: journal block not found "
"at offset %lu on %s\n",
__func__, blocknr, journal->j_devname);
err = -EIO;
__journal_abort_soft(journal, err);
} else {
*retp = block;
}
} else {
*retp = blocknr; /* +journal->j_blk_offset */
}
......@@ -1244,11 +1249,14 @@ journal_t *jbd2_journal_init_dev(struct block_device *bdev,
journal_t *jbd2_journal_init_inode(struct inode *inode)
{
journal_t *journal;
sector_t blocknr;
char *p;
unsigned long long blocknr;
int err = 0;
blocknr = 0;
err = bmap(inode, &blocknr);
blocknr = bmap(inode, 0);
if (!blocknr) {
if (err || !blocknr) {
pr_err("%s: Cannot locate journal superblock\n",
__func__);
return NULL;
......
......@@ -2865,9 +2865,16 @@ static inline ssize_t generic_write_sync(struct kiocb *iocb, ssize_t count)
extern void emergency_sync(void);
extern void emergency_remount(void);
#ifdef CONFIG_BLOCK
extern sector_t bmap(struct inode *, sector_t);
extern int bmap(struct inode *inode, sector_t *block);
#else
static inline int bmap(struct inode *inode, sector_t *block)
{
return -EINVAL;
}
#endif
extern int notify_change(struct dentry *, struct iattr *, struct inode **);
extern int inode_permission(struct inode *, int);
extern int generic_permission(struct inode *, int);
......
......@@ -177,8 +177,9 @@ int generic_swapfile_activate(struct swap_info_struct *sis,
cond_resched();
first_block = bmap(inode, probe_block);
if (first_block == 0)
first_block = probe_block;
ret = bmap(inode, &first_block);
if (ret || !first_block)
goto bad_bmap;
/*
......@@ -193,9 +194,11 @@ int generic_swapfile_activate(struct swap_info_struct *sis,
block_in_page++) {
sector_t block;
block = bmap(inode, probe_block + block_in_page);
if (block == 0)
block = probe_block + block_in_page;
ret = bmap(inode, &block);
if (ret || !block)
goto bad_bmap;
if (block != first_block + block_in_page) {
/* Discontiguity */
probe_block++;
......
Supports Markdown
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment