[GFS2] Fix page lock/glock deadlock
This fixes a race between the glock and the page lock encountered during truncate in gfs2_readpage and gfs2_prepare_write. The gfs2_readpages function doesn't need the same fix since it only uses a try lock anyway, so it will fail back to gfs2_readpage in the case of a potential deadlock. This bug was spotted by Russell Cattelan. Cc: Russell Cattelan <cattelan@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This commit is contained in:
parent
c594d88664
commit
2ca99501fa
|
@ -27,7 +27,6 @@
|
||||||
#define GL_ATIME 0x00000200
|
#define GL_ATIME 0x00000200
|
||||||
#define GL_NOCACHE 0x00000400
|
#define GL_NOCACHE 0x00000400
|
||||||
#define GL_NOCANCEL 0x00001000
|
#define GL_NOCANCEL 0x00001000
|
||||||
#define GL_AOP 0x00004000
|
|
||||||
|
|
||||||
#define GLR_TRYFAILED 13
|
#define GLR_TRYFAILED 13
|
||||||
#define GLR_CANCELED 14
|
#define GLR_CANCELED 14
|
||||||
|
|
|
@ -230,7 +230,7 @@ static int gfs2_readpage(struct file *file, struct page *page)
|
||||||
/* gfs2_sharewrite_nopage has grabbed the ip->i_gl already */
|
/* gfs2_sharewrite_nopage has grabbed the ip->i_gl already */
|
||||||
goto skip_lock;
|
goto skip_lock;
|
||||||
}
|
}
|
||||||
gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME|GL_AOP, &gh);
|
gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME|LM_FLAG_TRY_1CB, &gh);
|
||||||
do_unlock = 1;
|
do_unlock = 1;
|
||||||
error = gfs2_glock_nq_m_atime(1, &gh);
|
error = gfs2_glock_nq_m_atime(1, &gh);
|
||||||
if (unlikely(error))
|
if (unlikely(error))
|
||||||
|
@ -254,6 +254,8 @@ skip_lock:
|
||||||
out:
|
out:
|
||||||
return error;
|
return error;
|
||||||
out_unlock:
|
out_unlock:
|
||||||
|
if (error == GLR_TRYFAILED)
|
||||||
|
error = AOP_TRUNCATED_PAGE;
|
||||||
unlock_page(page);
|
unlock_page(page);
|
||||||
if (do_unlock)
|
if (do_unlock)
|
||||||
gfs2_holder_uninit(&gh);
|
gfs2_holder_uninit(&gh);
|
||||||
|
@ -293,7 +295,7 @@ static int gfs2_readpages(struct file *file, struct address_space *mapping,
|
||||||
goto skip_lock;
|
goto skip_lock;
|
||||||
}
|
}
|
||||||
gfs2_holder_init(ip->i_gl, LM_ST_SHARED,
|
gfs2_holder_init(ip->i_gl, LM_ST_SHARED,
|
||||||
LM_FLAG_TRY_1CB|GL_ATIME|GL_AOP, &gh);
|
LM_FLAG_TRY_1CB|GL_ATIME, &gh);
|
||||||
do_unlock = 1;
|
do_unlock = 1;
|
||||||
ret = gfs2_glock_nq_m_atime(1, &gh);
|
ret = gfs2_glock_nq_m_atime(1, &gh);
|
||||||
if (ret == GLR_TRYFAILED)
|
if (ret == GLR_TRYFAILED)
|
||||||
|
@ -366,10 +368,13 @@ static int gfs2_prepare_write(struct file *file, struct page *page,
|
||||||
unsigned int write_len = to - from;
|
unsigned int write_len = to - from;
|
||||||
|
|
||||||
|
|
||||||
gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME|GL_AOP, &ip->i_gh);
|
gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME|LM_FLAG_TRY_1CB, &ip->i_gh);
|
||||||
error = gfs2_glock_nq_m_atime(1, &ip->i_gh);
|
error = gfs2_glock_nq_m_atime(1, &ip->i_gh);
|
||||||
if (error)
|
if (unlikely(error)) {
|
||||||
|
if (error == GLR_TRYFAILED)
|
||||||
|
error = AOP_TRUNCATED_PAGE;
|
||||||
goto out_uninit;
|
goto out_uninit;
|
||||||
|
}
|
||||||
|
|
||||||
gfs2_write_calc_reserv(ip, write_len, &data_blocks, &ind_blocks);
|
gfs2_write_calc_reserv(ip, write_len, &data_blocks, &ind_blocks);
|
||||||
|
|
||||||
|
|
Loading…
Reference in New Issue