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GFS2: New truncate sequence
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This updates GFS2's truncate code to use the new truncate
sequence correctly. This is a stepping stone to being
able to remove ip->i_disksize in favour of using i_size
everywhere now that the two sizes are always identical.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
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Steven Whitehouse committed Sep 20, 2010
1 parent 2422084 commit ff8f33c
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Showing 4 changed files with 135 additions and 168 deletions.
10 changes: 4 additions & 6 deletions fs/gfs2/aops.c
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Original file line number Diff line number Diff line change
Expand Up @@ -696,13 +696,11 @@ static int gfs2_write_begin(struct file *file, struct address_space *mapping,

page_cache_release(page);

/*
* XXX(truncate): the call below should probably be replaced with
* a call to the gfs2-specific truncate blocks helper to actually
* release disk blocks..
*/
gfs2_trans_end(sdp);
if (pos + len > ip->i_inode.i_size)
truncate_setsize(&ip->i_inode, ip->i_inode.i_size);
gfs2_trim_blocks(&ip->i_inode);
goto out_trans_fail;

out_endtrans:
gfs2_trans_end(sdp);
out_trans_fail:
Expand Down
247 changes: 119 additions & 128 deletions fs/gfs2/bmap.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -50,7 +50,7 @@ struct strip_mine {
* @ip: the inode
* @dibh: the dinode buffer
* @block: the block number that was allocated
* @private: any locked page held by the caller process
* @page: The (optional) page. This is looked up if @page is NULL
*
* Returns: errno
*/
Expand Down Expand Up @@ -109,8 +109,7 @@ static int gfs2_unstuffer_page(struct gfs2_inode *ip, struct buffer_head *dibh,
/**
* gfs2_unstuff_dinode - Unstuff a dinode when the data has grown too big
* @ip: The GFS2 inode to unstuff
* @unstuffer: the routine that handles unstuffing a non-zero length file
* @private: private data for the unstuffer
* @page: The (optional) page. This is looked up if the @page is NULL
*
* This routine unstuffs a dinode and returns it to a "normal" state such
* that the height can be grown in the traditional way.
Expand Down Expand Up @@ -884,84 +883,15 @@ static int do_strip(struct gfs2_inode *ip, struct buffer_head *dibh,
return error;
}

/**
* do_grow - Make a file look bigger than it is
* @ip: the inode
* @size: the size to set the file to
*
* Called with an exclusive lock on @ip.
*
* Returns: errno
*/

static int do_grow(struct gfs2_inode *ip, u64 size)
{
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
struct gfs2_alloc *al;
struct buffer_head *dibh;
int error;

al = gfs2_alloc_get(ip);
if (!al)
return -ENOMEM;

error = gfs2_quota_lock_check(ip);
if (error)
goto out;

al->al_requested = sdp->sd_max_height + RES_DATA;

error = gfs2_inplace_reserve(ip);
if (error)
goto out_gunlock_q;

error = gfs2_trans_begin(sdp,
sdp->sd_max_height + al->al_rgd->rd_length +
RES_JDATA + RES_DINODE + RES_STATFS + RES_QUOTA, 0);
if (error)
goto out_ipres;

error = gfs2_meta_inode_buffer(ip, &dibh);
if (error)
goto out_end_trans;

if (size > sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)) {
if (gfs2_is_stuffed(ip)) {
error = gfs2_unstuff_dinode(ip, NULL);
if (error)
goto out_brelse;
}
}

ip->i_disksize = size;
ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
gfs2_dinode_out(ip, dibh->b_data);

out_brelse:
brelse(dibh);
out_end_trans:
gfs2_trans_end(sdp);
out_ipres:
gfs2_inplace_release(ip);
out_gunlock_q:
gfs2_quota_unlock(ip);
out:
gfs2_alloc_put(ip);
return error;
}


/**
* gfs2_block_truncate_page - Deal with zeroing out data for truncate
*
* This is partly borrowed from ext3.
*/
static int gfs2_block_truncate_page(struct address_space *mapping)
static int gfs2_block_truncate_page(struct address_space *mapping, loff_t from)
{
struct inode *inode = mapping->host;
struct gfs2_inode *ip = GFS2_I(inode);
loff_t from = inode->i_size;
unsigned long index = from >> PAGE_CACHE_SHIFT;
unsigned offset = from & (PAGE_CACHE_SIZE-1);
unsigned blocksize, iblock, length, pos;
Expand Down Expand Up @@ -1023,9 +953,11 @@ static int gfs2_block_truncate_page(struct address_space *mapping)
return err;
}

static int trunc_start(struct gfs2_inode *ip, u64 size)
static int trunc_start(struct inode *inode, u64 oldsize, u64 newsize)
{
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
struct address_space *mapping = inode->i_mapping;
struct buffer_head *dibh;
int journaled = gfs2_is_jdata(ip);
int error;
Expand All @@ -1039,31 +971,27 @@ static int trunc_start(struct gfs2_inode *ip, u64 size)
if (error)
goto out;

gfs2_trans_add_bh(ip->i_gl, dibh, 1);

if (gfs2_is_stuffed(ip)) {
u64 dsize = size + sizeof(struct gfs2_dinode);
ip->i_disksize = size;
ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
gfs2_dinode_out(ip, dibh->b_data);
if (dsize > dibh->b_size)
dsize = dibh->b_size;
gfs2_buffer_clear_tail(dibh, dsize);
error = 1;
gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode) + newsize);
} else {
if (size & (u64)(sdp->sd_sb.sb_bsize - 1))
error = gfs2_block_truncate_page(ip->i_inode.i_mapping);

if (!error) {
ip->i_disksize = size;
ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
ip->i_diskflags |= GFS2_DIF_TRUNC_IN_PROG;
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
gfs2_dinode_out(ip, dibh->b_data);
if (newsize & (u64)(sdp->sd_sb.sb_bsize - 1)) {
error = gfs2_block_truncate_page(mapping, newsize);
if (error)
goto out_brelse;
}
ip->i_diskflags |= GFS2_DIF_TRUNC_IN_PROG;
}

brelse(dibh);
i_size_write(inode, newsize);
ip->i_disksize = newsize;
ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
gfs2_dinode_out(ip, dibh->b_data);

truncate_pagecache(inode, oldsize, newsize);
out_brelse:
brelse(dibh);
out:
gfs2_trans_end(sdp);
return error;
Expand Down Expand Up @@ -1143,86 +1071,149 @@ static int trunc_end(struct gfs2_inode *ip)

/**
* do_shrink - make a file smaller
* @ip: the inode
* @size: the size to make the file
* @truncator: function to truncate the last partial block
* @inode: the inode
* @oldsize: the current inode size
* @newsize: the size to make the file
*
* Called with an exclusive lock on @ip.
* Called with an exclusive lock on @inode. The @size must
* be equal to or smaller than the current inode size.
*
* Returns: errno
*/

static int do_shrink(struct gfs2_inode *ip, u64 size)
static int do_shrink(struct inode *inode, u64 oldsize, u64 newsize)
{
struct gfs2_inode *ip = GFS2_I(inode);
int error;

error = trunc_start(ip, size);
error = trunc_start(inode, oldsize, newsize);
if (error < 0)
return error;
if (error > 0)
if (gfs2_is_stuffed(ip))
return 0;

error = trunc_dealloc(ip, size);
if (!error)
error = trunc_dealloc(ip, newsize);
if (error == 0)
error = trunc_end(ip);

return error;
}

static int do_touch(struct gfs2_inode *ip, u64 size)
void gfs2_trim_blocks(struct inode *inode)
{
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
u64 size = inode->i_size;
int ret;

ret = do_shrink(inode, size, size);
WARN_ON(ret != 0);
}

/**
* do_grow - Touch and update inode size
* @inode: The inode
* @size: The new size
*
* This function updates the timestamps on the inode and
* may also increase the size of the inode. This function
* must not be called with @size any smaller than the current
* inode size.
*
* Although it is not strictly required to unstuff files here,
* earlier versions of GFS2 have a bug in the stuffed file reading
* code which will result in a buffer overrun if the size is larger
* than the max stuffed file size. In order to prevent this from
* occuring, such files are unstuffed, but in other cases we can
* just update the inode size directly.
*
* Returns: 0 on success, or -ve on error
*/

static int do_grow(struct inode *inode, u64 size)
{
struct gfs2_inode *ip = GFS2_I(inode);
struct gfs2_sbd *sdp = GFS2_SB(inode);
struct buffer_head *dibh;
struct gfs2_alloc *al = NULL;
int error;

error = gfs2_trans_begin(sdp, RES_DINODE, 0);
if (gfs2_is_stuffed(ip) &&
(size > (sdp->sd_sb.sb_bsize - sizeof(struct gfs2_dinode)))) {
al = gfs2_alloc_get(ip);
if (al == NULL)
return -ENOMEM;

error = gfs2_quota_lock_check(ip);
if (error)
goto do_grow_alloc_put;

al->al_requested = 1;
error = gfs2_inplace_reserve(ip);
if (error)
goto do_grow_qunlock;
}

error = gfs2_trans_begin(sdp, RES_DINODE + 1, 0);
if (error)
return error;
goto do_grow_release;

down_write(&ip->i_rw_mutex);
if (al) {
error = gfs2_unstuff_dinode(ip, NULL);
if (error)
goto do_end_trans;
}

error = gfs2_meta_inode_buffer(ip, &dibh);
if (error)
goto do_touch_out;
goto do_end_trans;

i_size_write(inode, size);
ip->i_disksize = size;
ip->i_inode.i_mtime = ip->i_inode.i_ctime = CURRENT_TIME;
gfs2_trans_add_bh(ip->i_gl, dibh, 1);
gfs2_dinode_out(ip, dibh->b_data);
brelse(dibh);

do_touch_out:
up_write(&ip->i_rw_mutex);
do_end_trans:
gfs2_trans_end(sdp);
do_grow_release:
if (al) {
gfs2_inplace_release(ip);
do_grow_qunlock:
gfs2_quota_unlock(ip);
do_grow_alloc_put:
gfs2_alloc_put(ip);
}
return error;
}

/**
* gfs2_truncatei - make a file a given size
* @ip: the inode
* @size: the size to make the file
* @truncator: function to truncate the last partial block
* gfs2_setattr_size - make a file a given size
* @inode: the inode
* @newsize: the size to make the file
*
* The file size can grow, shrink, or stay the same size.
* The file size can grow, shrink, or stay the same size. This
* is called holding i_mutex and an exclusive glock on the inode
* in question.
*
* Returns: errno
*/

int gfs2_truncatei(struct gfs2_inode *ip, u64 size)
int gfs2_setattr_size(struct inode *inode, u64 newsize)
{
int error;
int ret;
u64 oldsize;

if (gfs2_assert_warn(GFS2_SB(&ip->i_inode), S_ISREG(ip->i_inode.i_mode)))
return -EINVAL;
BUG_ON(!S_ISREG(inode->i_mode));

if (size > ip->i_disksize)
error = do_grow(ip, size);
else if (size < ip->i_disksize)
error = do_shrink(ip, size);
else
/* update time stamps */
error = do_touch(ip, size);
ret = inode_newsize_ok(inode, newsize);
if (ret)
return ret;

return error;
oldsize = inode->i_size;
if (newsize >= oldsize)
return do_grow(inode, newsize);

return do_shrink(inode, oldsize, newsize);
}

int gfs2_truncatei_resume(struct gfs2_inode *ip)
Expand Down
20 changes: 11 additions & 9 deletions fs/gfs2/bmap.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -44,14 +44,16 @@ static inline void gfs2_write_calc_reserv(const struct gfs2_inode *ip,
}
}

int gfs2_unstuff_dinode(struct gfs2_inode *ip, struct page *page);
int gfs2_block_map(struct inode *inode, sector_t lblock, struct buffer_head *bh, int create);
int gfs2_extent_map(struct inode *inode, u64 lblock, int *new, u64 *dblock, unsigned *extlen);

int gfs2_truncatei(struct gfs2_inode *ip, u64 size);
int gfs2_truncatei_resume(struct gfs2_inode *ip);
int gfs2_file_dealloc(struct gfs2_inode *ip);
int gfs2_write_alloc_required(struct gfs2_inode *ip, u64 offset,
unsigned int len);
extern int gfs2_unstuff_dinode(struct gfs2_inode *ip, struct page *page);
extern int gfs2_block_map(struct inode *inode, sector_t lblock,
struct buffer_head *bh, int create);
extern int gfs2_extent_map(struct inode *inode, u64 lblock, int *new,
u64 *dblock, unsigned *extlen);
extern int gfs2_setattr_size(struct inode *inode, u64 size);
extern void gfs2_trim_blocks(struct inode *inode);
extern int gfs2_truncatei_resume(struct gfs2_inode *ip);
extern int gfs2_file_dealloc(struct gfs2_inode *ip);
extern int gfs2_write_alloc_required(struct gfs2_inode *ip, u64 offset,
unsigned int len);

#endif /* __BMAP_DOT_H__ */
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