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gfs2: Never call gfs2_block_zero_range with an open transaction

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Before this patch, some functions started transactions then they called
gfs2_block_zero_range. However, gfs2_block_zero_range, like writes, can
start transactions, which results in a recursive transaction error.
For example:

do_shrink
   trunc_start
      gfs2_trans_begin <------------------------------------------------
         gfs2_block_zero_range
            iomap_zero_range(inode, from, length, NULL, &gfs2_iomap_ops);
               iomap_apply ... iomap_zero_range_actor
                  iomap_begin
                     gfs2_iomap_begin
                        gfs2_iomap_begin_write
                  actor (iomap_zero_range_actor)
		     iomap_zero
			iomap_write_begin
			   gfs2_iomap_page_prepare
			      gfs2_trans_begin <------------------------

This patch reorders the callers of gfs2_block_zero_range so that they
only start their transactions after the call. It also adds a BUG_ON to
ensure this doesn't happen again.

Fixes: 2257e468a6 ("gfs2: implement gfs2_block_zero_range using iomap_zero_range")
Cc: stable@vger.kernel.org # v5.5+
Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
This commit is contained in:
Bob Peterson 2020-07-24 12:06:31 -05:00 committed by Andreas Gruenbacher
parent b0be23b23f
commit 70499cdfeb
1 changed files with 39 additions and 30 deletions
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69
fs/gfs2/bmap.c
View File

@ -1351,9 +1351,15 @@ int gfs2_extent_map(struct inode *inode, u64 lblock, int *new, u64 *dblock, unsi
return ret;
}
/*
* NOTE: Never call gfs2_block_zero_range with an open transaction because it
* uses iomap write to perform its actions, which begin their own transactions
* (iomap_begin, page_prepare, etc.)
*/
static int gfs2_block_zero_range(struct inode *inode, loff_t from,
unsigned int length)
{
BUG_ON(current->journal_info);
return iomap_zero_range(inode, from, length, NULL, &gfs2_iomap_ops);
}
@ -1414,6 +1420,16 @@ static int trunc_start(struct inode *inode, u64 newsize)
u64 oldsize = inode->i_size;
int error;
if (!gfs2_is_stuffed(ip)) {
unsigned int blocksize = i_blocksize(inode);
unsigned int offs = newsize & (blocksize - 1);
if (offs) {
error = gfs2_block_zero_range(inode, newsize,
blocksize - offs);
if (error)
return error;
}
}
if (journaled)
error = gfs2_trans_begin(sdp, RES_DINODE + RES_JDATA, GFS2_JTRUNC_REVOKES);
else
@ -1427,19 +1443,10 @@ static int trunc_start(struct inode *inode, u64 newsize)
gfs2_trans_add_meta(ip->i_gl, dibh);
if (gfs2_is_stuffed(ip)) {
if (gfs2_is_stuffed(ip))
gfs2_buffer_clear_tail(dibh, sizeof(struct gfs2_dinode) + newsize);
} else {
unsigned int blocksize = i_blocksize(inode);
unsigned int offs = newsize & (blocksize - 1);
if (offs) {
error = gfs2_block_zero_range(inode, newsize,
blocksize - offs);
if (error)
goto out;
}
else
ip->i_diskflags |= GFS2_DIF_TRUNC_IN_PROG;
}
i_size_write(inode, newsize);
ip->i_inode.i_mtime = ip->i_inode.i_ctime = current_time(&ip->i_inode);
@ -2448,25 +2455,7 @@ int __gfs2_punch_hole(struct file *file, loff_t offset, loff_t length)
loff_t start, end;
int error;
start = round_down(offset, blocksize);
end = round_up(offset + length, blocksize) - 1;
error = filemap_write_and_wait_range(inode->i_mapping, start, end);
if (error)
return error;
if (gfs2_is_jdata(ip))
error = gfs2_trans_begin(sdp, RES_DINODE + 2 * RES_JDATA,
GFS2_JTRUNC_REVOKES);
else
error = gfs2_trans_begin(sdp, RES_DINODE, 0);
if (error)
return error;
if (gfs2_is_stuffed(ip)) {
error = stuffed_zero_range(inode, offset, length);
if (error)
goto out;
} else {
if (!gfs2_is_stuffed(ip)) {
unsigned int start_off, end_len;
start_off = offset & (blocksize - 1);
@ -2489,6 +2478,26 @@ int __gfs2_punch_hole(struct file *file, loff_t offset, loff_t length)
}
}
start = round_down(offset, blocksize);
end = round_up(offset + length, blocksize) - 1;
error = filemap_write_and_wait_range(inode->i_mapping, start, end);
if (error)
return error;
if (gfs2_is_jdata(ip))
error = gfs2_trans_begin(sdp, RES_DINODE + 2 * RES_JDATA,
GFS2_JTRUNC_REVOKES);
else
error = gfs2_trans_begin(sdp, RES_DINODE, 0);
if (error)
return error;
if (gfs2_is_stuffed(ip)) {
error = stuffed_zero_range(inode, offset, length);
if (error)
goto out;
}
if (gfs2_is_jdata(ip)) {
BUG_ON(!current->journal_info);
gfs2_journaled_truncate_range(inode, offset, length);