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authorSteven Whitehouse <swhiteho@redhat.com>2006-11-08 10:26:54 -0500
committerSteven Whitehouse <swhiteho@redhat.com>2006-11-30 10:34:43 -0500
commit2ca99501fa5422e84f18333918a503433449e2b5 (patch)
tree46bdb25c3be5bdc4e4c80b30a99dd3811f2ee1c0 /fs
parentc594d8866460a2710c436839d79f334a0714a2a7 (diff)
[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>
Diffstat (limited to 'fs')
-rw-r--r--fs/gfs2/glock.h1
-rw-r--r--fs/gfs2/ops_address.c13
2 files changed, 9 insertions, 5 deletions
diff --git a/fs/gfs2/glock.h b/fs/gfs2/glock.h
index b9856274df59..a331bf8175ea 100644
--- a/fs/gfs2/glock.h
+++ b/fs/gfs2/glock.h
@@ -27,7 +27,6 @@
27#define GL_ATIME 0x00000200 27#define GL_ATIME 0x00000200
28#define GL_NOCACHE 0x00000400 28#define GL_NOCACHE 0x00000400
29#define GL_NOCANCEL 0x00001000 29#define GL_NOCANCEL 0x00001000
30#define GL_AOP 0x00004000
31 30
32#define GLR_TRYFAILED 13 31#define GLR_TRYFAILED 13
33#define GLR_CANCELED 14 32#define GLR_CANCELED 14
diff --git a/fs/gfs2/ops_address.c b/fs/gfs2/ops_address.c
index 5c3962c80e88..3822189454a3 100644
--- a/fs/gfs2/ops_address.c
+++ b/fs/gfs2/ops_address.c
@@ -230,7 +230,7 @@ static int gfs2_readpage(struct file *file, struct page *page)
230 /* gfs2_sharewrite_nopage has grabbed the ip->i_gl already */ 230 /* gfs2_sharewrite_nopage has grabbed the ip->i_gl already */
231 goto skip_lock; 231 goto skip_lock;
232 } 232 }
233 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME|GL_AOP, &gh); 233 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME|LM_FLAG_TRY_1CB, &gh);
234 do_unlock = 1; 234 do_unlock = 1;
235 error = gfs2_glock_nq_m_atime(1, &gh); 235 error = gfs2_glock_nq_m_atime(1, &gh);
236 if (unlikely(error)) 236 if (unlikely(error))
@@ -254,6 +254,8 @@ skip_lock:
254out: 254out:
255 return error; 255 return error;
256out_unlock: 256out_unlock:
257 if (error == GLR_TRYFAILED)
258 error = AOP_TRUNCATED_PAGE;
257 unlock_page(page); 259 unlock_page(page);
258 if (do_unlock) 260 if (do_unlock)
259 gfs2_holder_uninit(&gh); 261 gfs2_holder_uninit(&gh);
@@ -293,7 +295,7 @@ static int gfs2_readpages(struct file *file, struct address_space *mapping,
293 goto skip_lock; 295 goto skip_lock;
294 } 296 }
295 gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 297 gfs2_holder_init(ip->i_gl, LM_ST_SHARED,
296 LM_FLAG_TRY_1CB|GL_ATIME|GL_AOP, &gh); 298 LM_FLAG_TRY_1CB|GL_ATIME, &gh);
297 do_unlock = 1; 299 do_unlock = 1;
298 ret = gfs2_glock_nq_m_atime(1, &gh); 300 ret = gfs2_glock_nq_m_atime(1, &gh);
299 if (ret == GLR_TRYFAILED) 301 if (ret == GLR_TRYFAILED)
@@ -366,10 +368,13 @@ static int gfs2_prepare_write(struct file *file, struct page *page,
366 unsigned int write_len = to - from; 368 unsigned int write_len = to - from;
367 369
368 370
369 gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME|GL_AOP, &ip->i_gh); 371 gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, GL_ATIME|LM_FLAG_TRY_1CB, &ip->i_gh);
370 error = gfs2_glock_nq_m_atime(1, &ip->i_gh); 372 error = gfs2_glock_nq_m_atime(1, &ip->i_gh);
371 if (error) 373 if (unlikely(error)) {
374 if (error == GLR_TRYFAILED)
375 error = AOP_TRUNCATED_PAGE;
372 goto out_uninit; 376 goto out_uninit;
377 }
373 378
374 gfs2_write_calc_reserv(ip, write_len, &data_blocks, &ind_blocks); 379 gfs2_write_calc_reserv(ip, write_len, &data_blocks, &ind_blocks);
375 380