Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-10 22:21:40 +00:00
Code Issues Packages Projects Releases Wiki Activity

GFS2: Test bufdata with buffer locked and gfs2_log_lock held

Browse Source 
In gfs2_trans_add_bh(), gfs2 was testing if a there was a bd attached to the
buffer without having the gfs2_log_lock held. It was then assuming it would
stay attached for the rest of the function. However, without either the log
lock being held of the buffer locked, __gfs2_ail_flush() could detach bd at any
time.  This patch moves the locking before the test.  If there isn't a bd
already attached, gfs2 can safely allocate one and attach it before locking.
There is no way that the newly allocated bd could be on the ail list,
and thus no way for __gfs2_ail_flush() to detach it.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This commit is contained in:
Benjamin Marzinski 2012-11-07 00:38:06 -06:00 committed by Steven Whitehouse
parent 3d1626889a
commit 96e5d1d3ad
2 changed files with 10 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
fs/gfs2/lops.c
View File

@ -393,12 +393,10 @@ static void buf_lo_add(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
struct gfs2_meta_header *mh;
struct gfs2_trans *tr;
lock_buffer(bd->bd_bh);
gfs2_log_lock(sdp);
tr = current->journal_info;
tr->tr_touched = 1;
if (!list_empty(&bd->bd_list))
goto out;
return;
set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
set_bit(GLF_DIRTY, &bd->bd_gl->gl_flags);
mh = (struct gfs2_meta_header *)bd->bd_bh->b_data;
@ -414,9 +412,6 @@ static void buf_lo_add(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
sdp->sd_log_num_buf++;
list_add(&bd->bd_list, &sdp->sd_log_le_buf);
tr->tr_num_buf_new++;
out:
gfs2_log_unlock(sdp);
unlock_buffer(bd->bd_bh);
}
static void gfs2_check_magic(struct buffer_head *bh)
@ -775,12 +770,10 @@ static void databuf_lo_add(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
struct address_space *mapping = bd->bd_bh->b_page->mapping;
struct gfs2_inode *ip = GFS2_I(mapping->host);
lock_buffer(bd->bd_bh);
gfs2_log_lock(sdp);
if (tr)
tr->tr_touched = 1;
if (!list_empty(&bd->bd_list))
goto out;
return;
set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
set_bit(GLF_DIRTY, &bd->bd_gl->gl_flags);
if (gfs2_is_jdata(ip)) {
@ -791,9 +784,6 @@ static void databuf_lo_add(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
} else {
list_add_tail(&bd->bd_list, &sdp->sd_log_le_ordered);
}
out:
gfs2_log_unlock(sdp);
unlock_buffer(bd->bd_bh);
}
/**

8
fs/gfs2/trans.c
View File

@ -155,14 +155,22 @@ void gfs2_trans_add_bh(struct gfs2_glock *gl, struct buffer_head *bh, int meta)
struct gfs2_sbd *sdp = gl->gl_sbd;
struct gfs2_bufdata *bd;
lock_buffer(bh);
gfs2_log_lock(sdp);
bd = bh->b_private;
if (bd)
gfs2_assert(sdp, bd->bd_gl == gl);
else {
gfs2_log_unlock(sdp);
unlock_buffer(bh);
gfs2_attach_bufdata(gl, bh, meta);
bd = bh->b_private;
lock_buffer(bh);
gfs2_log_lock(sdp);
}
lops_add(sdp, bd);
gfs2_log_unlock(sdp);
unlock_buffer(bh);
}
void gfs2_trans_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)