[PATCH v2 01/26] pstore: allow for big files

From: dragos.tatulea@intel.com
To: linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org, cjb@laptop.org
Cc: kirill.shutemov@linux.intel.com, irina.tirdea@intel.com,
	octavian.purdila@intel.com, tony.luck@intel.com,
	keescook@chromium.org, dragos.tatulea@gmail.com,
	Adrian Hunter <adrian.hunter@intel.com>
Subject: [PATCH v2 01/26] pstore: allow for big files
Date: Thu,  8 Nov 2012 15:05:59 +0200	[thread overview]
Message-ID: <1352379984-18381-2-git-send-email-dragos.tatulea@intel.com> (raw)
In-Reply-To: <1352379984-18381-1-git-send-email-dragos.tatulea@intel.com>

From: Adrian Hunter <adrian.hunter@intel.com>

pstore reads all files into memory at mount time. To allow for back ends
that will store arbitrarily large files, enhance pstore also to be able
to read from the back end as needed.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
---
 drivers/acpi/apei/erst.c |   16 +++++++++-------
 fs/pstore/inode.c        |   26 ++++++++++++++++++++------
 fs/pstore/internal.h     |    5 +++--
 fs/pstore/platform.c     |   11 +++++++----
 fs/pstore/ram.c          |   15 +++++++--------
 include/linux/pstore.h   |    7 +++++--
 6 files changed, 51 insertions(+), 29 deletions(-)

diff --git a/drivers/acpi/apei/erst.c b/drivers/acpi/apei/erst.c
index e4d9d24..f70ba37 100644
--- a/drivers/acpi/apei/erst.c
+++ b/drivers/acpi/apei/erst.c
@@ -931,9 +931,9 @@ static int erst_check_table(struct acpi_table_erst *erst_tab)
 
 static int erst_open_pstore(struct pstore_info *psi);
 static int erst_close_pstore(struct pstore_info *psi);
-static ssize_t erst_reader(u64 *id, enum pstore_type_id *type,
-			   struct timespec *time, char **buf,
-			   struct pstore_info *psi);
+static int erst_reader(u64 *id, enum pstore_type_id *type,
+		       struct timespec *time, char **buf, loff_t *size,
+		       struct pstore_info *psi);
 static int erst_writer(enum pstore_type_id type, enum kmsg_dump_reason reason,
 		       u64 *id, unsigned int part,
 		       size_t size, struct pstore_info *psi);
@@ -987,9 +987,9 @@ static int erst_close_pstore(struct pstore_info *psi)
 	return 0;
 }
 
-static ssize_t erst_reader(u64 *id, enum pstore_type_id *type,
-			   struct timespec *time, char **buf,
-			   struct pstore_info *psi)
+static int erst_reader(u64 *id, enum pstore_type_id *type,
+		       struct timespec *time, char **buf, loff_t *size,
+		       struct pstore_info *psi)
 {
 	int rc;
 	ssize_t len = 0;
@@ -1051,7 +1051,9 @@ skip:
 
 out:
 	kfree(rcd);
-	return (rc < 0) ? rc : (len - sizeof(*rcd));
+	if (!rc)
+		*size = len - sizeof(*rcd);
+	return rc;
 }
 
 static int erst_writer(enum pstore_type_id type, enum kmsg_dump_reason reason,
diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index 4ab572e..ff0970f 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -49,7 +49,8 @@ struct pstore_private {
 	struct pstore_info *psi;
 	enum pstore_type_id type;
 	u64	id;
-	ssize_t	size;
+	loff_t	size;
+	bool	big;
 	char	data[];
 };
 
@@ -65,12 +66,13 @@ static void *pstore_ftrace_seq_start(struct seq_file *s, loff_t *pos)
 {
 	struct pstore_private *ps = s->private;
 	struct pstore_ftrace_seq_data *data;
+	loff_t size = ps->size;
 
 	data = kzalloc(sizeof(*data), GFP_KERNEL);
 	if (!data)
 		return NULL;
 
-	data->off = ps->size % REC_SIZE;
+	data->off = do_div(size,  REC_SIZE);
 	data->off += *pos * REC_SIZE;
 	if (data->off + REC_SIZE > ps->size) {
 		kfree(data);
@@ -127,6 +129,12 @@ static ssize_t pstore_file_read(struct file *file, char __user *userbuf,
 
 	if (ps->type == PSTORE_TYPE_FTRACE)
 		return seq_read(file, userbuf, count, ppos);
+	if (ps->big) {
+		if (ps->psi->file_read)
+			return ps->psi->file_read(ps->id, ps->type, userbuf,
+						count, ppos, ps->psi);
+		return -EFBIG;
+	}
 	return simple_read_from_buffer(userbuf, count, ppos, ps->data, ps->size);
 }
 
@@ -271,8 +279,8 @@ int pstore_is_mounted(void)
  * Set the mtime & ctime to the date that this record was originally stored.
  */
 int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
-		  char *data, size_t size, struct timespec time,
-		  struct pstore_info *psi)
+		  char *data, loff_t size, struct timespec time,
+		  struct pstore_info *psi, bool big)
 {
 	struct dentry		*root = pstore_sb->s_root;
 	struct dentry		*dentry;
@@ -281,6 +289,7 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
 	char			name[PSTORE_NAMELEN];
 	struct pstore_private	*private, *pos;
 	unsigned long		flags;
+	size_t			inline_size;
 
 	spin_lock_irqsave(&allpstore_lock, flags);
 	list_for_each_entry(pos, &allpstore, list) {
@@ -301,12 +310,17 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
 		goto fail;
 	inode->i_mode = S_IFREG | 0444;
 	inode->i_fop = &pstore_file_operations;
-	private = kmalloc(sizeof *private + size, GFP_KERNEL);
+	if (big)
+		inline_size = 0;
+	else
+		inline_size = size;
+	private = kmalloc(sizeof(*private) + inline_size, GFP_KERNEL);
 	if (!private)
 		goto fail_alloc;
 	private->type = type;
 	private->id = id;
 	private->psi = psi;
+	private->big = big;
 
 	switch (type) {
 	case PSTORE_TYPE_DMESG:
@@ -336,7 +350,7 @@ int pstore_mkfile(enum pstore_type_id type, char *psname, u64 id,
 	if (IS_ERR(dentry))
 		goto fail_lockedalloc;
 
-	memcpy(private->data, data, size);
+	memcpy(private->data, data, inline_size);
 	inode->i_size = private->size = size;
 
 	inode->i_private = private;
diff --git a/fs/pstore/internal.h b/fs/pstore/internal.h
index 4847f58..f840159 100644
--- a/fs/pstore/internal.h
+++ b/fs/pstore/internal.h
@@ -50,8 +50,9 @@ extern struct pstore_info *psinfo;
 extern void	pstore_set_kmsg_bytes(int);
 extern void	pstore_get_records(int);
 extern int	pstore_mkfile(enum pstore_type_id, char *psname, u64 id,
-			      char *data, size_t size,
-			      struct timespec time, struct pstore_info *psi);
+			      char *data, loff_t size,
+			      struct timespec time, struct pstore_info *psi,
+			      bool big);
 extern int	pstore_is_mounted(void);
 
 #endif
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index a40da07..108bd69 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -264,7 +264,7 @@ void pstore_get_records(int quiet)
 {
 	struct pstore_info *psi = psinfo;
 	char			*buf = NULL;
-	ssize_t			size;
+	loff_t			size;
 	u64			id;
 	enum pstore_type_id	type;
 	struct timespec		time;
@@ -277,9 +277,12 @@ void pstore_get_records(int quiet)
 	if (psi->open && psi->open(psi))
 		goto out;
 
-	while ((size = psi->read(&id, &type, &time, &buf, psi)) > 0) {
-		rc = pstore_mkfile(type, psi->name, id, buf, (size_t)size,
-				  time, psi);
+	while (1) {
+		rc = psi->read(&id, &type, &time, &buf, &size, psi);
+		if (rc && rc != -EFBIG)
+			break;
+		rc = pstore_mkfile(type, psi->name, id, buf, size,
+				  time, psi, rc == -EFBIG);
 		kfree(buf);
 		buf = NULL;
 		if (rc && (rc != -EEXIST || !quiet))
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 1a4f6da..dd47a87 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -131,12 +131,11 @@ ramoops_get_next_prz(struct persistent_ram_zone *przs[], uint *c, uint max,
 	return prz;
 }
 
-static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
+static int ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
 				   struct timespec *time,
-				   char **buf,
+				   char **buf, loff_t *size,
 				   struct pstore_info *psi)
 {
-	ssize_t size;
 	struct ramoops_context *cxt = psi->data;
 	struct persistent_ram_zone *prz;
 
@@ -150,19 +149,19 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
 		prz = ramoops_get_next_prz(&cxt->fprz, &cxt->ftrace_read_cnt,
 					   1, id, type, PSTORE_TYPE_FTRACE, 0);
 	if (!prz)
-		return 0;
+		return -EINVAL;
 
 	/* TODO(kees): Bogus time for the moment. */
 	time->tv_sec = 0;
 	time->tv_nsec = 0;
 
-	size = persistent_ram_old_size(prz);
-	*buf = kmalloc(size, GFP_KERNEL);
+	*size = persistent_ram_old_size(prz);
+	*buf = kmalloc(*size, GFP_KERNEL);
 	if (*buf == NULL)
 		return -ENOMEM;
-	memcpy(*buf, persistent_ram_old(prz), size);
+	memcpy(*buf, persistent_ram_old(prz), *size);
 
-	return size;
+	return 0;
 }
 
 static size_t ramoops_write_kmsg_hdr(struct persistent_ram_zone *prz)
diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index ee3034a..3a293ff 100644
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -49,8 +49,11 @@ struct pstore_info {
 	struct mutex	read_mutex;	/* serialize open/read/close */
 	int		(*open)(struct pstore_info *psi);
 	int		(*close)(struct pstore_info *psi);
-	ssize_t		(*read)(u64 *id, enum pstore_type_id *type,
-			struct timespec *time, char **buf,
+	int		(*read)(u64 *id, enum pstore_type_id *type,
+			struct timespec *time, char **buf, loff_t *size,
+			struct pstore_info *psi);
+	ssize_t		(*file_read)(u64 id, enum pstore_type_id type,
+			char __user *userbuf, size_t count, loff_t *ppos,
 			struct pstore_info *psi);
 	int		(*write)(enum pstore_type_id type,
 			enum kmsg_dump_reason reason, u64 *id,
-- 
1.7.9.5

