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authorSteven Whitehouse <swhiteho@redhat.com>2006-08-04 15:41:22 -0400
committerSteven Whitehouse <swhiteho@redhat.com>2006-08-04 15:41:22 -0400
commit59a1cc6bdabf5ed148b48808ad1a418d87f5e6bf (patch)
tree6463071a09201040267702e895d63359e62c393d
parent899bb264507cfed83922bf14cd66a073494601ba (diff)
[GFS2] Fix lock ordering bug in page fault path
Mmapped files were able to trigger a lock ordering bug. Private maps do not need to take the glock so early on. Shared maps do unfortunately, however we can get around that by adding a flag into the flags for the struct gfs2_file. This only works because we are taking an exclusive lock at this point, so we know that nobody else can be racing with us. Fixes Red Hat bugzilla: #201196 Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
-rw-r--r--fs/gfs2/incore.h1
-rw-r--r--fs/gfs2/log.c4
-rw-r--r--fs/gfs2/ops_address.c23
-rw-r--r--fs/gfs2/ops_vm.c20
-rw-r--r--fs/gfs2/recovery.c9
5 files changed, 32 insertions, 25 deletions
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 90e0624d806..e98c14f30da 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -279,6 +279,7 @@ static inline struct gfs2_sbd *GFS2_SB(struct inode *inode)
enum {
GFF_DID_DIRECT_ALLOC = 0,
+ GFF_EXLOCK = 1,
};
struct gfs2_file {
diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 60fdc94ccc8..a591fb8fae2 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -256,8 +256,8 @@ static unsigned int current_tail(struct gfs2_sbd *sdp)
if (list_empty(&sdp->sd_ail1_list))
tail = sdp->sd_log_head;
else {
- ai = list_entry(sdp->sd_ail1_list.prev,
- struct gfs2_ail, ai_list);
+ ai = list_entry(sdp->sd_ail1_list.prev, struct gfs2_ail,
+ ai_list);
tail = ai->ai_first;
}
diff --git a/fs/gfs2/ops_address.c b/fs/gfs2/ops_address.c
index fca69f12e4d..bdd4d6b4872 100644
--- a/fs/gfs2/ops_address.c
+++ b/fs/gfs2/ops_address.c
@@ -237,14 +237,22 @@ static int gfs2_readpage(struct file *file, struct page *page)
struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
struct gfs2_holder gh;
int error;
+ int do_unlock = 0;
if (likely(file != &gfs2_internal_file_sentinal)) {
+ if (file) {
+ struct gfs2_file *gf = file->private_data;
+ if (test_bit(GFF_EXLOCK, &gf->f_flags))
+ goto skip_lock;
+ }
gfs2_holder_init(ip->i_gl, LM_ST_SHARED, GL_ATIME|GL_AOP, &gh);
+ do_unlock = 1;
error = gfs2_glock_nq_m_atime(1, &gh);
if (unlikely(error))
goto out_unlock;
}
+skip_lock:
if (gfs2_is_stuffed(ip)) {
error = stuffed_readpage(ip, page);
unlock_page(page);
@@ -262,7 +270,7 @@ out:
return error;
out_unlock:
unlock_page(page);
- if (file != &gfs2_internal_file_sentinal)
+ if (do_unlock)
gfs2_holder_uninit(&gh);
goto out;
}
@@ -291,17 +299,24 @@ static int gfs2_readpages(struct file *file, struct address_space *mapping,
struct gfs2_holder gh;
unsigned page_idx;
int ret;
+ int do_unlock = 0;
if (likely(file != &gfs2_internal_file_sentinal)) {
+ if (file) {
+ struct gfs2_file *gf = file->private_data;
+ if (test_bit(GFF_EXLOCK, &gf->f_flags))
+ goto skip_lock;
+ }
gfs2_holder_init(ip->i_gl, LM_ST_SHARED,
LM_FLAG_TRY_1CB|GL_ATIME|GL_AOP, &gh);
+ do_unlock = 1;
ret = gfs2_glock_nq_m_atime(1, &gh);
if (ret == GLR_TRYFAILED)
goto out_noerror;
if (unlikely(ret))
goto out_unlock;
}
-
+skip_lock:
if (gfs2_is_stuffed(ip)) {
struct pagevec lru_pvec;
pagevec_init(&lru_pvec, 0);
@@ -326,7 +341,7 @@ static int gfs2_readpages(struct file *file, struct address_space *mapping,
ret = mpage_readpages(mapping, pages, nr_pages, gfs2_get_block);
}
- if (likely(file != &gfs2_internal_file_sentinal)) {
+ if (do_unlock) {
gfs2_glock_dq_m(1, &gh);
gfs2_holder_uninit(&gh);
}
@@ -344,7 +359,7 @@ out_unlock:
unlock_page(page);
page_cache_release(page);
}
- if (likely(file != &gfs2_internal_file_sentinal))
+ if (do_unlock)
gfs2_holder_uninit(&gh);
goto out;
}
diff --git a/fs/gfs2/ops_vm.c b/fs/gfs2/ops_vm.c
index aff66373b7e..875a769444a 100644
--- a/fs/gfs2/ops_vm.c
+++ b/fs/gfs2/ops_vm.c
@@ -46,13 +46,7 @@ static struct page *gfs2_private_nopage(struct vm_area_struct *area,
unsigned long address, int *type)
{
struct gfs2_inode *ip = GFS2_I(area->vm_file->f_mapping->host);
- struct gfs2_holder i_gh;
struct page *result;
- int error;
-
- error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &i_gh);
- if (error)
- return NULL;
set_bit(GIF_PAGED, &ip->i_flags);
@@ -61,8 +55,6 @@ static struct page *gfs2_private_nopage(struct vm_area_struct *area,
if (result && result != NOPAGE_OOM)
pfault_be_greedy(ip);
- gfs2_glock_dq_uninit(&i_gh);
-
return result;
}
@@ -141,7 +133,9 @@ static int alloc_page_backing(struct gfs2_inode *ip, struct page *page)
static struct page *gfs2_sharewrite_nopage(struct vm_area_struct *area,
unsigned long address, int *type)
{
- struct gfs2_inode *ip = GFS2_I(area->vm_file->f_mapping->host);
+ struct file *file = area->vm_file;
+ struct gfs2_file *gf = file->private_data;
+ struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);
struct gfs2_holder i_gh;
struct page *result = NULL;
unsigned long index = ((address - area->vm_start) >> PAGE_CACHE_SHIFT) +
@@ -156,13 +150,14 @@ static struct page *gfs2_sharewrite_nopage(struct vm_area_struct *area,
set_bit(GIF_PAGED, &ip->i_flags);
set_bit(GIF_SW_PAGED, &ip->i_flags);
- error = gfs2_write_alloc_required(ip,
- (uint64_t)index << PAGE_CACHE_SHIFT,
+ error = gfs2_write_alloc_required(ip, (u64)index << PAGE_CACHE_SHIFT,
PAGE_CACHE_SIZE, &alloc_required);
if (error)
goto out;
+ set_bit(GFF_EXLOCK, &gf->f_flags);
result = filemap_nopage(area, address, type);
+ clear_bit(GFF_EXLOCK, &gf->f_flags);
if (!result || result == NOPAGE_OOM)
goto out;
@@ -177,8 +172,7 @@ static struct page *gfs2_sharewrite_nopage(struct vm_area_struct *area,
}
pfault_be_greedy(ip);
-
- out:
+out:
gfs2_glock_dq_uninit(&i_gh);
return result;
diff --git a/fs/gfs2/recovery.c b/fs/gfs2/recovery.c
index 7aabc03e4ab..bbd44a4b1a1 100644
--- a/fs/gfs2/recovery.c
+++ b/fs/gfs2/recovery.c
@@ -153,8 +153,7 @@ static int get_log_header(struct gfs2_jdesc *jd, unsigned int blk,
if (lh.lh_header.mh_magic != GFS2_MAGIC ||
lh.lh_header.mh_type != GFS2_METATYPE_LH ||
- lh.lh_blkno != blk ||
- lh.lh_hash != hash)
+ lh.lh_blkno != blk || lh.lh_hash != hash)
return 1;
*head = lh;
@@ -482,11 +481,9 @@ int gfs2_recover_journal(struct gfs2_jdesc *jd)
/* Acquire a shared hold on the transaction lock */
- error = gfs2_glock_nq_init(sdp->sd_trans_gl,
- LM_ST_SHARED,
+ error = gfs2_glock_nq_init(sdp->sd_trans_gl, LM_ST_SHARED,
LM_FLAG_NOEXP | LM_FLAG_PRIORITY |
- GL_NOCANCEL | GL_NOCACHE,
- &t_gh);
+ GL_NOCANCEL | GL_NOCACHE, &t_gh);
if (error)
goto fail_gunlock_ji;